gs2165 physics lab manual

Time: 2 hours (GS2165) - C H E M I S T R Y L A B O R A T O R Y

Maximum marks: 50

1. Calculate the amount of temporary hardness of the given water sample. You are H^j}^ r\£$^ provided with standard hard water, link EDTA, sample water & boiled sample water.

2. Estimate the amount of bicarbonate and carbonate ions present in the given water sample. You are provided with HC1 M K a ] ! AA ^ ^

3. Out of the two samples given which contain more chloride ions. You are provided with a standard AgN03 solution. C-Vilofvt h$*

4. Find out which contain more copper out of the two samples. You are provided with a standard EDTA solution. ' / x £ o f f $ % 3 C\ 5

5. Calculate the amount of H2SO4 present in the given solution using conductometer and a standard alkali, c ^ 5 6 C o r t A W d c £ $

6. Estimate the amount of HC1 and Acetic acid present in the given solution using conductometer and a standard alkali. <TU^

7. Using pH meter calculate the amount of HC1 present in the given solution, you are provided with a standard alkali. ^ ^ ^

Short procedure 1 semester

Name of experiment

Burette solution

Pipette solution

Additional solution

Indicator Colour change

(end point)

Formula Equiva t weig

1.DETERMINATION OF TOTAL, PERMANENT AND TEMPORARY HARDNESS OF WATER SAMPLE (EDTA METHOD) Titration 1 EDTA Std .hard water 5 ml

ammonia, buffer

EBT Wine red -steel blue

20 x Mgs

Titration 2 Std. EDTA Given sample water

5 ml ammonia,

buffer


v 2

1000 x Mgs

2. ESTIMATION OF COPPER IN BRASS BY EDTA METHOD Titration 1 EDTA Std .Znso 4

solution 10 ml ammonia. Buffer


V J N J XV 2 N 2

Titration 2 Std. EDTA Cuso 4 solution 5 ml borate buffer

Muroxide Orange-blue violet

Amount =N X Atomic mass of cu

At .wt. of cu =63.54

3. E s t i m a t i o n of d i s so l ved o x y g e n in w a t e r ( W i n k l e r ' s m e t h o d ) Titration 1 (Standardisation of sodium thio sulphate)

Sodium thio sulphate

Std. Potassium di chromate solution

5 ml H 2 s o 4

+ 7ml 5% Kl Starch Blue -light

green VjNiXV 2 N 2

Titration 2 (Estimation of D O )

Std.Sodium thio sulphate

Sample water

Cone H2S04+2ml mangane'se Sulphate +2ml

Starch Blue -colourless

Amount =M X Eq. w t . o f O j

Eq . wt .of Cb = 8

•"tracer .

. _ . _ , • - - - * - . .

E a « t - o f E a « t - o f

D r o w n 5. E s t imat ion of Alkal in i ty in w a t e r sample

Titration 1 (Phenolphthalein indicator)

S td . HCL

W a t e r

s a m p l e Phenolpht halein

P i n k -

co lour less

( i ) Olf alkal in i ty =

2[P]-[M] (ii) co3-alkal in i ty

= 2 [ M ] - [ P ]

Titration 2

•

M e t h y l -

orange

Colour less

- red

orange

V J N J = V 2 N 2

Amount =M X Eq. wt .of CaCo 3

Eq . w t of CaCo 3

f

Short procedure 11 s e m e s t e r

solution Pipette solution

Additional solution

Model graph

Colour change (end

point)

Formula Equivalent weight

"Conductometric titration of strong Acid with strong base

NaOH 20ml Std. HCL

30 ml of Conductivity water

Decrease in conductance - increase in conductance

ViNi = V 2 N 2

Amount =M X Eq. wt .of NaOH

Eq. wt .of NaOH =40

8. Conductometric titration of mixture of acids [HCL & CH3COOH )

Std. NaOH 20ml Mixture of acids( HCL + CH3COOH )

30 ml of Conductivity water

Conductivity decrease -slowly increase - sudden increase

V aNi = V 2 N 2

i. Amount =M X Eq. wt .of HCL ii. Amount =M X Eq.

wt.of CH3COOH

Eq. wt .of HCL= 36.5 Eq. wt .of CH3COOH= 60

9. Conductometric Precipitation titration using BaCU- Na,Soa

Std. Na2So4 20ml BaCI2

30 ml conductivity Water

•—

conductivity decrease -increase

V 1N 1 = V 2 N 2

i. Amount =M X Eq. wt .of BaCI2

Eq. wt .of BaCI2 = 122.14

30 ml conductivity Water

•—

Eq. wt .of BaCI2 = 122.14

10. Estimation of ferrous iron by potentiometric titration

Std. K2Cr207 Ferrous iron solution

20ml of dis. Water+ 10ml Dil. H2SO4

Emf increase-decreases

ViNi = V 2 N 2

i. Amount =M X Eq. wt .of Fe2+

Eq. wt .of Fe2+ = 55.85

etry - Determination of HCI by NaOH

HCI 20 ml distilled pH gradual ViNi = V 2N 2 Eq. wt .of water increases- i. Amount =M X Eq. HCI =36.5

sudden wt .of HCI increase

3

Physics Lab Manual

M.A.M School of Engineering Page 3 Department of Physics

LIST OF EXPERIMENTS

S. No EXPERIMENTS

1. Determination of the Young’s modulus for the given uniform bar by uniform bending method

2. Determination of the wavelength of the diode laser and hence determine the size of the coated powder particle

3. Determination of the velocity of Ultrasonic using Ultrasonic interferometer. Also find the compressibility of the given liquid

4. Determination of the moment of inertia of the given circular disc and rigidity modulus of the metal wire using torsional pendulum

5. Determination of the Young’s modulus of the given wooden uniform material using non-uniform bending method

6. Determination of the angle and dispersive of the given solid prism using spectrometer

7. Determination of the thickness of the given thin material by forming interference fringes using air-wedge setup

8. Determination of the wavelength of prominent lines of Hg spectrum using spectrometer

9. Determination of the energy gap of the given semiconductor by plotting the graph between current and temperature

10. Determination of the co-efficient of viscosity of the given liquid by Poiseuille’s method. Radius of the capillary tube is 0.035 cm

Physics Lab Manual


Fig. 1 Young’s Modulus – Uniform Bending

Fig. 2 Model Graph

Physics Lab Manual


DETERMINATION OF YOUNG’S MODULUS OF THE MATERIAL OF A BAR – UNIFORM BENDING

Aim

To determine the young’s modulus of the material of a uniform bar by uniform bending method

Apparatus Required

• Traveling microscope • Two knife edges

• Meter scale

• Screw gauge.

• Weight hanger with slotted weights • Pin

• Vernier caliper

Principle

When a beam symmetrically supported on two knife edge is loaded at its both ends with equal weights at an equal distance from the nearest knife edge, the bent beam would form an arc of circle. This type of bending is called uniform bending. The maximum elevation is produced at its mid point.

Formula

The Young’s Modulus of the material of the uniform bar,

Symbol Explanation Unit

g Acceleration to due to gravity ms-2

a Distance between the weight hanger and nearest knife edge m

l Distance between the two knife edges m

b Breadth of the beam m

d Thickness of the beam m

y Elevation produced for ‘M’ kg of load m

M Load considered to calculate elevation Kg.

23

2

2

3 −= Nmy

M

bd

galY

Expt. No.: Date:

Physics Lab Manual


Table. 1Find elevation ‘y’

Distance between two knife edges (l) = _____ X 10 -2 m

LC=0.001 X 10 -2 m TR = MSR + (VSC X LC)

Microscope Reading

Loading Unloading S .No Load

MSR VSC TR MSR VSC TR

Mean

Elevation y

for ‘M’ kg

Unit X10-3 kg X10-2 m div X10-2m X10-2m div X10-2m X10-2 m X10-2 m

1 W

2 W+50

3 W+100

4 W+150

5 W+200

6 W+250

Mean elevation ( y) = _______ mX 210−

Physics Lab Manual


Procedure

When a beam is loaded at the both end of the beam from the equal distance ‘a’ from the knife edge , the beam would form an arc of a circle. This type of bending is called uniform bending.

The given beam is placed over the knife edges A and B at a particular distance say 70 cm or 80 cm in the same horizontal levels. The hanger is placed both end of the beam at the equal distance ‘a’ from the knife edges. At the centre of the bar, a pin is fixed using wax as shown if fig. 1.

The load in steps of 50 g will be added on the both sides of the beam using hanger and hence, there will be the corresponding elevation , which can be measured using the traveling microscope.

Taking the weight hanger alone as the dead load , the midpoint of the pin is focused by the microscope, and is adjusted in such a way that the tip of the pin touches with the horizontal cross wire. The reading on the vertical scale is noted. Now the weight is added in the steps of 50 g on both hangers. Each time, the tip of the pin is made to tough the horizontal cross wire and the readings are noted from the vertical scale of the microscope.

By unloading the weight in steps of same 50 g the readings are tabulated in table. The thickness (d) and the breadth (b) of the beam are measured using the screw gauge and vernier caliper respectively. Substituting the values in equation, Young’s modulus can be calculated.

Physics Lab Manual


Table. 2 To find the breadth (b) of the beam using vernier caliper

LC = 0.01 X 10-2 m ZE = ______ mX 210−

ZC = ______ mX 210−

S. No

Main Scale Reading

(MSR)

Vernier Scale Concidence

(VSC)

Observed Reading

OR = MSR+(VSC X LC)

Correct Reading

= OR ± ZC

Unit mX 210− div. mX 210−

mX 210−

1.

2.

3.

4.

5.

Mean (b) = _______ mX 210−

Table. 3 To find the thickness (d) of the beam using screw guage

LC = 0.01 X 10-3 m ZE = _____ mX 310−

ZC = ______ mX 310−

S. No

Pitch Scale Reading

(PSR)

Head Scale Concidence

(HSC)

Observed Reading

OR = PSR+(HSC X LC)

Correct Reading

= OR ± ZC

Unit mX 310− div. mX 310−

mX 310−

1.

2.

3.

4.

5.

Mean (d) = _______ mX 310−

Physics Lab Manual


Calculation

Acceleration to due to gravity g = 9.8 ms-2

Distance between the weight hanger and nearest knife edge a = m

Distance between the two knife edges l = m

Breadth of the beam b = m

Thickness of the beam d = m

Elevation produced for ‘M’ kg of load y = m

Load to calculate elevation m = kg

The Young’s modulus of the given material of the beam

2__________ −= NmY

Result

(i) The Young’s Modulus of the given uniform beam Y= ____________2−Nm

(ii)By graphical method the Young’s modulus of the given uniform beam Y= ____________2−Nm

2

3

2

2

3 −= Nmy

M

bd

galY

Physics Lab Manual


Fig. 3 Wavelength of LASER

Table -1 : To find wavelength of the LASER source

S. No

Distance D

Order

X

Mean

X2 D2 √(X2+D2) λ

LHS RHS X Unit X10-2 m

X10-2 m X10-2 m X10-2 m X10-4 m2 X10-4

m2 X10-2 m Å

1. 1

2 2

3 3

4 4

5 1

6 2

7 3

8 4

9 1

10 2

11 3

12 4

Mean λ

Physics Lab Manual


LASER

DETERMINATION OF WAVELENGTH OF LASER LIGHT USING GRATING

DETERMINATION OF PARTICLE SIZE ANGLE OF DIVERGENCE & ACCEPTANCE ANGLE

Aim To determine,

(i) Wavelength of the given laser source, using a LASER grating. (ii) Particle size of the given powder using LASER source. (iii) Angle of divergence using LASER source. (iv) Numerical aperture and acceptance angle.

Apparatus Required

� Laser source � Grating � Lycopodium powder � Screen

� Scale � Optical fiber � Numerical aperture jig

Formula

(i) Wavelength of the laser source, λ= X Å

(ii) The size of the particle,

m

(iii) Angle of divergence,

Φ = r2- r1 / d2- d1 degree

(iv) Numerical aperture of the optical fiber

r NA = No unit

(v) Acceptance angle

max = Sin -1 NA degree

22 D+XNm

Y

D+Y =d

21

2mλ

22 d+r

Expt. No.: Date:

Physics Lab Manual


Fig. 4 Size of the particle

Fig. 5 Diffraction pattern

Table -2 : To find the size of the given particle

S. No

Distance D1

Order

Y

Mean

Y2 D12 √(Y2+D1

2) d

LHS RHS Ym Unit X10-2 m

X10-2 m X10-2 m X10-2 m X10-2 m X10-4 m2 X10-2 m X10-6 m

1 1

2 2

3 1

4 2

5 1

6 2

Mean d

Physics Lab Manual



X , Y The distance from mth order to 0th order in diffraction Pattern m

N The number of lines per meter in the grating lines/m

m The order of diffraction pattern no unit

D The distance between the particle and the screen m D1 The distance between the laser grating and the screen m

r Radius of the circular opening in NA jig m

d Distance between the tip of the optical fiber and NA jig m

Procedure (i) Calculation of the wavelength of the laser source The laser source and the laser grating are mounted on separate stands as shown in fig.3. A fixed distance (D) is kept between the laser grating and the screen. The laser source is switched ON and the beam of laser is allowed to fall on the laser grating. The diffracted beams are collected on the screen. The diffracted beams are in the form of spots as shown in fig.3. From the figure the intensity of the irradiance is found to decrease from 0-th order to higher orders, i.e., the first order is brighter than the second order and so on. The positions X1 , X2 , X3, ……….Xm of the spots belongs to the first order , second order , third order etc., On either side of the central maximum are marked on the screen and is noted. The experiment is repeated for various values of D and the positions of the spots are noted. Then, by using the given equation the wavelength of the laser source can be calculated and the mean is taken.

(ii) Calculation of the size of the given particle Now the laser grating is removed and the powder consist of micro sized particle is introduced. The laser source is switched ON and the light is made to fall on the particle. The screen is moved back and forth until the clear image of the spectrum is seen and the distance between the screen and the particle (D1) is noted. Due to diffraction of the laser light by the particle, different orders of spectrum are obtained as shown in fig.4. The positions belongs to first order, second order etc. on either side of the central maximum are noted. Then, by using the given formula the size of the particle can be determined. (iii) Calculation of angle of divergence The laser source and stand is kept at some distance say d1 and the radius of the beam spot is measured and by varying the distance to d2, the radius of the beam spot is again measured. By substituting the values in the given formula the angle of divergence can be determined.

Physics Lab Manual


Fig. 5 Angle of divergence

Table – 3: To find the angle of divergence

S. No r1

d1

r 2 d2 Φ=d2-d1/r 2-r 1

Unit X10-2 m X10-2 m X10-2 m X10-4 m2 Degrees

1.

Physics Lab Manual


(vi) Calculation of the Numerical aperture by fiber optic method

A known length of fiber is taken. One end of the fiber is connected to the laser source and the other end is connected to the numerical aperture (NA) Jig as shown in fig.6. The source is switched ON. The opening in the NA jig is completely opened so that a circular red patch of laser light is observed on the screen. By opening in the jig is slowly closed with the knob provided, at a particular point the circular red patch of laser light is observed on the screen. By adjusting the opening in the NA Jig is slowly at particular points the circular light patch in the screen just cuts. The radius of the circular opening (r) of NA jig at which the circular patch of light just cuts is measured.

The distance between the NA jig and opening and the fiber can be measured directly with the help of the calibration in NA jig. By substituting the values in the given formula the NA can be calculated. By finding NA and substitute it in the given formula the acceptance angle can be calculated.

Calculation

(i) Wavelength of the laser source, λ = X Å

22 D+XNm

Physics Lab Manual


Fig.6. Numerical Aperture

Table 4. To find Numerical aperture

S. No Length of the given

fiber

Distance between NA jig opening &

fiber (d)

Radius of the circular opening in NA (r)

r NA =

- X 10-2 m X 10-2 m X 10-3 m -

1

2

3

4

5

Mean :

22 d+r

Physics Lab Manual


(ii) The size of the particle,

m

(iii) Angle of divergence

Φ = d2- d1/ r2- r1 degree

Y

D+Y =d

21

2mλ

Physics Lab Manual


(iv) Numerical Aperture

r NA = No unit

(v) Acceptance angle

max = Sin -1 NA degree

Results

(i) Wavelength of the laser source λ = __________ Å

(ii)The size of the particle d = ___________ m

(iii) Angle of divergence Φ = ___________ degree

(iv)Numerical Aperture NA = ___________ No unit

(v) Acceptance angle max = ___________ degree

22 d+r

Physics Lab Manual


Fig. 7 Ultrasonic Interferometer

Physics Lab Manual


ULTRASONIC INTERFEROMETER Aim

1. To determine the velocity of ultrasonic wave in the medium of different liquids using ultrasonic

interferometer. 2. To determine the compressibility of the given liquid.

Apparatus Required

Ultrasonic interferometer (High frequency generator, measuring cell) Given liquid.

Principle

High frequency generator, which excites the quartz crystal, generates the ultrasonic wave in the experimental liquid. The liquid will now serving as an acoustical grating element. Hence, when an ultrasonic wave passes through the ruling of gratings, successive maxima and minima occur, satisfying the condition for diffraction.

Formulae

1. Wavelength of the ultrasonic waves,

2. Velocity of ultrasonic wave in a given liquid,

3. Compressibility of the given liquid,


f Frequency of generator which excites the crystal Hz d Distance moved in micrometer screw m λ Wavelength of the ultrasonic wave m n Number of oscillations No unit ρ Density of the given liquid Kg/m3

mn

d2=λ

1−= msfV λ

122

1 −= NmKρν

Expt. No.: Date:

Physics Lab Manual


Table. 1 Calculation of the ultrasonic velocity (v) in the liquid

Given Liquid: _____________ Frequency of the generator f = 2 X 106 Hz

L.C = 0.001 cm

Micrometer Reading Number of

Maxima PSR HSC

TR=PSR+

(HSC X LC)

d

S. No

Unit X 10-3m div. X 10-3m X 10-3m X 10-3m m/s

1. n+5

2. n+10

3. n+15

4. n+20

5. n+25

6. n+30

n

d2=λ νλ=V

Physics Lab Manual


Description

Ultrasonic Interferometer technique gives a very accurate value in the measurement of sound velocity. The ultrasonic Interferometer consists of following parts are shown in fig

• High frequency generator, • Measuring cell.

High Frequency Generator It generates alternating field of variable frequencies. The frequency generator is used to excite the quartz plate placed at the bottom of the measuring cell at its resonant frequency. The excited quartz crystal generates ultrasonic waves in the experimental liquid in the measuring cell.

Measuring Cell Measuring cell shown in fig has a double walled vessel with a provision to maintain temperature constant. At the top of the cell a fine micrometer screw is fitted. With the help of the screw, the reflector plate placed in a cell can be lowered or raised through a known distance. The reflector and the quartz crystal (mounted at the bottom of the cell) are parallel to each other. When the alternating field from the frequency generator is applied to the crystal, it gets into resonant vibrations. Procedure The high frequency generator is switched on and the alternating field from the generator is applied to the quartz crystal. The quartz crystal produces longitudinal ultrasonic waves. The ultrasonic wave passes through the liquid and gets reflected at the surface of the reflector plate. If the distance between the reflector and crystal is exactly a whole multiple of the sound wavelength, standing waves are formed within the medium. This results in the formation of acoustics resonance and cause a change in the potential difference at the generator which excites the crystal. Due to this, anode current of the generator becomes maximum .The change in the anode current can be measured from the micrometer fitted with the frequency generator. The distance between the reflector and crystal is varied using the micrometer screw such that the anode current decreases from maximum and then increases up to a maximum. The distance of separation between successive maximum or minimum in the anode current is equal to half the wavelength of the ultrasonic waves in the liquid. By nothing the initial and final position of the micrometer for one complete oscillation (maxima-minima-maxima), one can determine the distance moved by the parallel reflector as shown Fig.7. Thus ‘n’ number of successive maxima or minima is recorded for a distance d. The total distance moved by the micrometer screw is given by

or Wavelength

2

λnd =

n

d2=λ

Physics Lab Manual


Calculation

Frequency of the generator f = x 10 6 Hz

Distance moved in micrometer screw d = m

Wavelength of the ultrasonic waves λ = m

Density of the given liquid ρ = Kg m-3

Number of oscillations n =

Wavelength of the ultrasonic waves,

λ= m

Velocity of ultrasonic wave in the given liquid,

V = ms-1

mn

d2=λ

1−= msfV λ

Physics Lab Manual


From the value of λ, the velocity of the longitudinal ultrasonic waves is calculated using the relation, V= fλ, where f is the frequency of the generator which is used to excite the crystal. After determining the velocity of the ultrasonic waves in liquid is calculated using the formula K=1/v2ρ where ρ is the density of the liquid. The experiment is repeated for different liquids. Compressibility of the given liquid,

K= m2N-1

Result

1. Velocity of the ultrasonic waves in the given liquid = ________________m/s. 2. Compressibility of the given liquid = _______________ m2/N

122

1 −= NmKρν

Physics Lab Manual


Fig. 8 Torsional pendulum

Fig. 9 Model Graph

Physics Lab Manual


22

12

2

20

21

22 )(2

mkgTT

TddmI

−−

=

242

0

8 −= mNrT

lIn

π

TORSIONAL PENDULUM - DETERMINATION OF MOMENT OF

INERTIA AND RIGIDITY MODULUS Aim To determine,

The moment of inertia of a given disc by Torsional oscillations and The rigidity modulus of the material of the suspension wire.

Apparatus Required

• Torsional pendulum • Stop clock • Meter scale

• Two symmetrical mass • Screw gauge.

Formula

Moment of inertia of the circular disc,

Rigidity modulus of them wire,


m mass of one cylinder placed on the disc kg

d1 Closest distance ( minimum) between suspension wire and the centre of mass of the cylinder

m

d2 Farthest distance ( maximum) between suspension wire and the centre of mass of the cylinder

m

T0 Period of oscillation without any mass on the disc s

T1 Period of oscillation when equal masses are placed on the disc at a distance d1 s

T2 Period of oscillation when equal masses are placed on the disc at a distance d2 s

l length of the suspension wire m

r Radius of the wire m

Expt. No.: Date:

Physics Lab Manual


Table.1 To find the period of oscillations of Torsional Pendulum

Length of the suspension wire (l) = ……… x 10-2 m

Table. 2 To find the radius of the wire by screw gauge

LC = 0.01 X10-3 m ZE = ……... X10-3 m

ZC = ……... mX 310−

S. No. Pitch scale Reading (PSR)

Head Scale Coincidence

(HSC)

Observed reading OR = PSR + (HSC X LC)

Correct Reading = OR ± ZC

Unit X 10 -3 m div. X 10 -3 m X 10 -3 m

1.

2.

3.

4.

5.

Mean =________ mX 310−

Radius of the wire (r) = Diameter

2

Time for 10 oscillations Position of the

Symmetrical

masses

Trial-1 Trial-2 Mean

Period of oscillation

Unit seconds seconds seconds seconds

Without masses T0 =

With masses at

d1= x10-2 m

T1 =

With masses at

d2= x10-2 m

T2 =

Physics Lab Manual


Principle

When the suspension wire is twisted by the circular disc fixed at the bottom of the wire, the wire undergoes shearing strain. This is called torsion. Because of this torsion, the disc executes oscillations called torsional oscillations. The angular acceleration of the disc is proportional to its angular displacement and is always directed towards its mean position. Hence, the motion of the disc is simple harmonic. Procedure When the suspension wire is twisted by the circular disc fixed at the bottom of the wire, the wire undergoes shearing strain. This is called torsion. Because of this torsion, the disc executes oscillation called torsional oscillation. The Torsional pendulum consists of a circular disc suspended by a thin suspended wire, as shown in Fig.8, whose rigidity modulus is to be noted. The top end of the wire is fixed by a chuck. The circular disc is attached to the other end of the wire. Calculation of T0

Adjust the wire so that its length is fixed value say 60 or 70 cm. Make a vertical chalk mark on the disc when it is rest as a reference. By making a small twist to the circular disc, set up Torsional oscillations. After the first few oscillations, just as the mark on the disc passes the equilibrium positions, a stop clock is started. The time taken for 10 complete oscillations is noted. The experiments is repeated for second trial and mean value is calculated. The mean value of the period is noted as T0. Calculation of T1

The two identical cylindrical masses are placed at equal distance on either side of the central chuck as close as possible. The distance d1 is measured between the wire and the centre of the cylindrical mass. By twisting the disc, the time taken for 10 complete oscillations is noted. The mean value of the time period is noted as T1. Calculation of T2

The identical masses are arranged symmetrically as far away from the axis of the rotation as possible. The distance d2 is measured between the centre of the cylindrical mass of the time taken for 10 complete oscillations is calculated in the same manner as that of the calculation of T0 and T1. Calculation of Moment Of Inertia and Rigidity Modulus The mean value of the radius and length of the wire is measured accurately by a screw gauge and meter scale respectively. The moment of the inertia of the circular disc and the rigidity modulus of the suspension wire are calculated by substituting the values in the equations respectively.

Physics Lab Manual


Table 3. To find L/T2

Time for 10 oscillations S. No

Length of suspension

wire (L) Trial 1 Trial 2 Mean

Time Period

T T2 L/ T 2

- X10-2 sec sec sec sec Sec2 m/s2

1

2

3

4

5

Physics Lab Manual


22

12

2

20

21

22 )(2

mkgTT

TddmI

−−

=

Calculation

Mean radius of the wire r = m

Length of the wire l = m

Mass of the identical cylinder m = kg

Closest distance between suspension wire & the centre of symmetrical mass d1 = m Farthest distance between suspension wire& the centre of symmetrical mass d2= m

Period of oscillations (without masses) T0 = sec

Period of oscillations with masses at ‘d1’ distance T1 = sec

Period of oscillations with masses at ‘d2’ distance T2 = sec

The moment of inertia of the circular disc,

Physics Lab Manual


242

0

8 −= mNrT

lIn

π

Rigidity modulus of the wire,

Result

(i) Moment of inertia of the circular disc I = _____________ kg m²

(ii) Rigidity modulus of the given wire n = ______________ Nm-2

(iii) By graphical method Rigidity Modulus n = ______________ Nm-2

Physics Lab Manual


Fig.10. Young’s modulus – non uniform bending

Fig.11. Model graph

Table .1 To find the breadth (b) of the beam using vernier caliper

LC = 0.01 x10-2m ZE = ______ mX 210−

ZC = ______ mX 210−

S. No. Main Scale

Reading (MSR)

Vernier Scale Concidence

(VSC)

Observed Reading OR = MSR+(VSC X LC)

Correct Reading

= OR ± ZC

Unit X 10 -2 m div. X 10 -2 m X 10 -2 m

1.

2.

3.

4.

5.

Mean (b) = ___________x10-2m

Physics Lab Manual


DETERMINATION OF YOUNG’S MODULUS OF THE MATERIAL OF AN UNIFORM BAR – NON UNIFORM BENDING

Aim To determine the young’s modulus of the material of a uniform bar by non uniform bending method.

Apparatus Required • Traveling microscope • Two knife edges • Meter scale

• Screw gauge.

• Weight hanger with slotted weights • Pin • Vernier caliper

Principle When a beam symmetrically supported on two knife edge is loaded at its centre, the bent beam

would not form an arc of circle. This type of bending is called non uniform bending. The maximum elevation is produced at its mid point.

Formula The Young’s Modulus of the material,


g Acceleration due to gravity ms-2

l Distance between the two knife edges m

b Breadth of the beam (meter scale) m

d Thickness of the beam (meter scale) m

y Depression produced for ‘M’ kg of load m

M Load applied kg

Procedure The given beam is placed over the knife edges A and B at a particular distance say 70 cm or

80 cm in the same horizontal levels. The hanger is placed at the centre of the knife edge and a pin is also fixed using wax as shown in fig.10.

The load in steps of 50 g will be added on the both sides of the beam using hanger and hence, there will be the corresponding elevation , which can be measured using the traveling Taking the weight hanger alone as the dead load , the midpoint of the pin is focused by the microscope, and is adjusted in such a way that the tip of the pin touches with the horizontal cross wire. The MSR & VSR reading on the vertical scale are noted. Now the weight is added in the steps

2

3

2

2

3 −= Nmy

M

bd

galY

Expt. No.: Date:

Physics Lab Manual


Table. 2 To find depression ‘y’

Distance between two knife edges (l) = _____ X 10 -2 m

LC=0.001x10-2m TR = MSR + (VSC X LC)

Microscope Reading

Loading Unloading S. No. Load

MSR VSC TR MSR VSC TR

Mean Depression

y for ‘M’ kg

Unit X 10 -3 kg X 10 -2 m div. X 10 -2 m X 10 -2 m div. X 10 -2 m X 10 -2 m X 10 -2 m

1. W

2. W+50

3. W+100

4. W+150

5. W+200

6. W+250

Mean elevation (y) = _________ mX 210−

Table. 3 To find the thickness (d) of the beam using screw guage

LC = 0.01 X 10-3 m ZE = _____ mX 310−

ZC = ______ mX 310−

S. No. Pitch Scale

Reading (PSR)

Head Scale Coincidence

(HSC)

Observed Reading OR = PSR +(HSC X LC)

Correct Reading = OR ± ZC

Unit X 10 -3 m div. X 10 -3 m X 10 -3 m

1.

2.

3.

4.

5.

Mean (d) = _______ mX 310−

Physics Lab Manual


of 50 g on hanger which is kept at the centre of the beam. Each time, the tip of the pin is made to tough the horizontal cross wire and the readings are noted from the vertical scale of the microscope.

By unloading the weight in steps of same 50 g the reading are tabulated in table. The thickness (d) and the breadth (b) of the beam are measured using the screw gauge and vernier caliper respectively. Substituting the values in equation, Young’s modulus can be calculated.

Calculation

Acceleration due to gravity g = 9.8 ms-2

Distance between the two knife edges l = m

Breadth of the beam b = m

Thickness of the beam d = m

Depression produced for ‘M’ kg of load y = m

Load to calculate depression M = kg

Physics Lab Manual


The Young’s modulus of the given material of the beam

2__________ −= NmY

Result The Young’s Modulus of the given uniform beam

(i) BY calculation Y = _______________ 2−Nm

(ii) By graphical method Y = _______________ 2−Nm

2

3

2

2

3 −= Nmy

M

bd

galY

Physics Lab Manual


Fig.12. Angle of prism (A)

Table .1 Calculation of angle of prism (A)

Least count =1’

Spectrometer reading 2A

A = 2A 2

Mean A

Vernier-A Vernier-B Reflected ray

MSR

(degree)

VSC div.

TR

(degree) MSR

(degree)

VSC div.

TR

(degree)

VA

(degree)

R1~R2

VB

(degree)

R3~R4

VA

(degree)

VB

(degree) Degrees

Right side

R1 R3

Left side

R2 R4

Physics Lab Manual


SPECTROMETER – DETERMINATION OF DISPERSIVE POWER OF A PRISM

Aim To determine,

(i) Refractive index of the prism and (ii) Dispersive power of the prism using spectrometer.

Apparatus Required

• Spectrometer • Glass prism • Sodium vapour lamp • Spirit level • Reading lens

Formula

• Refractive index of the given prism,

No unit

• Dispersive power of the prism, No unit

Symbol Explanation Unit A The angle of prism Degree

D The angle of minimum deviation Degree µ Refractive index of the prism for first colour No unit µ2 Refractive index of the prism for second colour No unit

+

=

2sin

2sin

A

DA

µ

12

21

21 −

+−=µµ

µµω

Expt. No.: Date:

Physics Lab Manual


Fig.13. Minimum deviation (D)

Physics Lab Manual


Procedure (i) Calculation of angle of prism

The initial adjustments of the spectrometer are made. The slit is illuminated by sodium vapour

lamp. The given prism is mounted on prism table such that the light emerging from the collimator should be made to incident on both the faces of the prism as shown in fig.12.

The telescope is rotated left or right to catch the image of the slit reflected by one face of the prism. The vertical cross wire is adjusted to coincide with reflected image. The MSR and VSC are noted on Vernier-A and Vernier-B. Similarly, readings are taken for the image reflected by the other face of the prism. The difference between the two reading are given the twice the angle of prism. From that angle of prism (A) is calculated.

(ii) Calculation of angle of minimum deviation (D) and refractive index (µ)

The prism is mounted such that light emerging from the collimator is incident on one of the

refractive face of the prism. The telescope is rotated to catch the refracted image of anyone of the colour which emerges from other refracting face of the prism.

Now by viewing through the telescope the prism table is slightly rotated in such a way that the

violet image moves towards the direct ray and at a particular position it retraces its original path. This position is called Minimum Deviation Position. The prism table is fixed and hence now all the colours in the prism are said to be into minimum deviation position as shown in fig.13. The tangential screw is adjusted to coincide with the image of each and every colour with the vertical cross wire and the readings are tabulated in table 2. The prism is removed and the direct ray reading is noted. The difference between the direct ray and the refracted ray readings for each colour gives the angle of minimum deviation (D) for that respective colour . Then by substituting the values of ‘D’ and ‘A’ in the equation 1, the refractive indices (µ) for each and every colour can be calculated.

(iii) Calculation of dispersion power

Finally by choosing any two colours with refractive indices as µandµ2 the dispersive power of

the prism is calculated using the equation 2. Similarly, for various values of µandµ2 the dispersive powers are calculated and the mean of all the dispersive powers is calculated.

Physics Lab Manual


Table. 2 Calculation of angle of minimum deviation (D) and refractive index (µ) LC=1’

SPECTROMETER READING D = R1-R2

VERNIER-A VERNIER-B

SPECTRAL LINES

MSR

(degree)

VSC div.

TR(R1)

(degree)

MSR

(degree)

VSC div.

TR(R2)

(degree)

D1

(degree)

R1~R3

D2

(degree)

R2~R4

MEAN

(degree)

�� DIRECT RAY R3 R4

VIOLET 1

VIOLET 2

BLUE

BLUISH GREEN

GREEN

YELLOW1

YELLOW2

RED

+

=

2sin

2sin

A

DA

µ

Physics Lab Manual


Calculation

Angle of prism A =_____________ degree. Angle of minimum deviation D =_____________ degree. Refractive index of the prism µ1 =_____________ no unit. Refractive index of the prism µ2 =_____________ no unit. Refractive index of the given prism, No unit Dispersive power of the prism, No unit

+

=

2sin

2sin

A

DA

µ

12

21

21 −

+−=µµ

µµω

Physics Lab Manual


Result

Angle of prism A =_____________ degree

Mean dispersive power of the prism ω =____________ no unit

Physics Lab Manual


Fig.14. Air wedge

Fig.15. Fringe Pattern

Physics Lab Manual


AIRWEDGE – DETERMINATION OF THICKNESS OF A THIN WIRE

Aim

To determine the thickness of the thin wire by forming the interference fringes using the air wedge set up.

Apparatus required

• Traveling microscope • Sodium vapor lamp

• Optically plane rectangular glass plates • Thin wire

• Reading lens • Condensing lens with stand

• Rubber band • Wooden box with glass plate inclined at 450

Formula Thickness of the thin wire,


l Distance between the edge of contact and the wire m

λ Wavelength of sodium light m

β Mean fringe width m

Principle

A wedge shaped air film is formed when a thin wire is introduced between two optically plane glass plates. When a parallel beam of monochromatic light is incident normally on this arrangement, interference occurs between the two rays; one is reflected from the front surfaces and the other at the back. These two reflected rays produce a pattern of alternate dark and bright interference fringes.

Procedure

Two optically plane glass plates are placed one over the other and are tie together by means of a rubber band at one end. The given thin wire is introduced in between the two glass plates, so that an air wedge is formed between the plates as shown in fig.14 this set up is placed on the horizontal bed plate of the traveling microscope.

ml

tβλ

2=

Expt. No.: Date:

Physics Lab Manual


Table. 1 To determine the fringe with (β) by traveling microscope

Least count = 0.001x10-2m

Microscope reading Order of

fringe MSR VSC TR Width of 10

fringes Mean width of 1 fringe β

Unit X 10-2 m div. X 10-2 m X 10-2 m X 10-2 m

n

n+5

n+10

n+15

n+20

n+25

n+30

n+35

n+40

n+45

Mean β=_________ mX 210−

Calculation Wavelength of the monochromatic light λ = 5893 Å

Distance between the edge of contact and the wire l = m

Fringe width β = m

Thickness of the wire,

t =

ml

tβλ

2=

Physics Lab Manual


The sodium vapor lamp is used as a source and is rendered parallel by means of a condensing lens. The parallel beam of light is incident on a plane glass plate inclined at an angle of 450 and gets reflected. The reflected light is incident normally on the glass plate in contact. Interference takes place between the light reflected from the top and bottom surfaces of the glass plate and is viewed through the traveling microscope. Therefore, the number of equally spaced dark and bright fringes are formed which are parallel to the edge of contact.

For the calculation of the single fringe width the microscope is adjusted so that the bright or dark fringe near the edge of contact is made to coincide with the vertical cross wire and this is taken as the nth fringe. The reading from the horizontal scale of the traveling microscope is noted. The microscope is moved across the fringes using the horizontal transverse screw and the readings are taken when the vertical cross wire coincides with every successive 3 fringes. The mean of this gives the fringe width (β).

The cross wire is fixed at the inner edge of the rubber band and the readings from the microscope is noted. Similarly reading from the microscope is noted keeping the cross wire at the edge of the material. The difference between these two values gives the value of ‘l ’. Substituting the value β and l in the equation then the thickness of the given thin wire can be determined.

RESULT

Thickness of the given thin wire t = ____________ x 10 -6 m

Physics Lab Manual


Fig.16 Normal incidence position Fig. 17 Spectrometer grating

Table 1. To fine the number of lines per meter of the grating

LC= 1’ order of the spectrum n = λ'= 5893 Å TR = MSR + (VSC x LC)

Spectrometer reading 2θ (R1~R2)

θ = 2θ 2

Mean θ

Vernier-A Vernier-B

Dif fracted eflected Ray Reading

MSR

(degree)

VSC div.

TR

(degree) MSR

(degree)

VSC div.

TR

(degree)

VA

(degree)

VB

(degree)

VA

(degree)

VB

(degree)

Degrees

Right side

R1 R1

Left side

R2 R2

Physics Lab Manual


SPECTROMETER – DETERMINATION OF WAVELENGTH OF

MERCURY SPECTRUM

Aim

To determine the wavelength of the mercury (Hg) spectrum by standardizing the plane transmission grating

Apparatus Required

• Spectrometer

• Plane transmission grating

• Mercury vapour lamp

• Sodium vapour lamp

• Spirit level

• Reading lens

Formula

• The number of lines drawn on the grating per meter

• The wavelength of the spectral lines of mercury spectrum


θ angle of diffraction degree

n order of the spectrum No unit

N Number of lines per meter in the grating No unit

λ Wave length of sodium vapour lamp 5893Å m

Principle

A Plane sheet of transparent material on which a large number of equidistant opaque rulings are made with a diamond point forms grating. The spaces between the rulings and transparent are constitute a parallel slit .When light passes through such a grating, diffraction takes place. Angle of diffraction depends upon the wavelength of the light and number of lines per meter on the grating. From this, the number of lines per meter in grating and wavelength of the source can be calculated.

mlinesn

SinN /

1λθ=

mNn

Sinθλ =

Expt. No.: Date:

Physics Lab Manual


Table. 1To determine the wavelength (λ) of the prominent lines of the mercury spectrum LC= 1’ order of the spectrum n = N = ____________ lines/ m TR = MSR + (VSC x LC)

Diffracted ray reading Difference (2θ)

2

2θθ =

Left side Right side

VERNIER-A VERNIER-B VERNIER-A VERNIER-B

Colour of

spectral lines

MS

R

VS

C

TR

MS

R

VS

C

TR

MS

R

VS

C

TR

MS

R

VS

C

TR

VA VB VA VB

ME

AN

θ

λ

UNIT

deg

div

deg

deg

div

deg

deg

div

deg

deg

div

deg

deg

deg

deg

deg

deg

Å

Violet-I

violet-II

Blue

Blue Green

Green

Yellow-I

Yellow-II

Red

Physics Lab Manual


Procedure

(i) Normal Incidence

Preliminary adjustments of the spectrometer are made. The grating is mounted on the grating table with its ruled surface facing the collimator the slit is illuminated by a source of light (sodium vapour lamp). The slit is made to coincide with the vertical cross wires. The vernier scales are adjusted to read 0˚ and 180˚ for the direct ray .The telescope is rotated through an angle of 90˚ and fixed. The grating table is adjusted until the image coincides with the vertical cross wire .Both the grating table and the telescope are fixed at this position as shown in Fig.13. Now rotate the vernier table through 45˚ in the same direction in which the telescope has been previously rotated. The light from the collimator incident normally on the grating. The telescope is released and is brought on the line with the direct image of the slit. Now the grating is said to be in normal incidence position

(ii) Calculation of Number of Lines per Meter (N) In Grating

The slit is illuminated by sodium vapour lamp, the telescope is released to get the diffracted image of the first order on the left side of the central direct image as shown in fig.16. The readings are tabulated from the two verniers VA and VB. Similarly readings are taken for the image of the first order on right side of the central direct image. The difference between the two readings gives 2θ, where θ is the angle of first order diffraction. The number of lines per meter (N) on the grating is calculated using the equation.

(iii) Determination of Wavelength (λ) of the Source

The sodium vapour lamp is replaced by mercury vapour lamp. The diffracted images of the first order are seen on either side of the central direct image as shown in Fig.17. The readings are tabulated by coincide the vertical cross wire with the first order on the either side of the central direct image prominent lines namely violet, blue, bluish green, green, yellow, red of the mercury spectrum. The difference between the readings give 2θ, from this θ can be found. The wavelength of each spectral line is calculated using the equation.

Physics Lab Manual


Calculation

Order of the spectrum n=1

Wavelength of sodium vapour lamp λ1=5893Å

Angle of Diffraction θ= degree

1. The number of lines drawn on the grating per meter,

N = ________ mlines/

2. The wavelength of the spectral lines of mercury spectrum,

λ =______m

mlinesn

SinN /

1λθ=

meterNn

Sinθλ =

Physics Lab Manual


Result

(i) The Number of Lines per meter in grating N= lines/meter

(ii) Wavelength of various spectral lines

Wavelength for violet λV = Å

Wavelength for blue λB= Å

Wavelength for bluish green λBG= Å

Wavelength for green λG= _Å

Wavelength for yellow λY= _Å

Wavelength for red λR = Å

Physics Lab Manual


Fig.18. Band gap

1000 / T

Log Is

Fig.19 . Model graph

Physics Lab Manual


DETERMINATION OF BAND GAP OF A SEMICONDUCTOR

Aim

To determine the band gap energy of a semiconductor by varying the temperature

Apparatus Required

• Semiconductor diode • Heating arrangement to heat the

diode

• Ammeter • Voltmeter

• Thermometer

Principle

For a semiconductor diode at 0K the valence band is completely filled and the conduction band is empty and it behaves as an insulator. If the temperature is increased, some of the valence electrons gains thermal energy greater than the forbidden energy (Eg) and it moves to conduction band, which constitutes some current to flow through the semiconductor diode.

Formula

Band gap Energy Eg = 0.198 x Slope eV

Slope = log I s / (1000/T)


I s Saturation current µA

T Absolute temperature Kelvin

Procedure

The circuit is given as shown in fig.18. The semiconductor diode and the thermometer is immersed in the water or oil bath, in such a way that the thermometer is kept nearby the diode. The power supply is kept constant (2 Volts). The heating mantle is switch ON and the oil bath is heated upto 70oC. Now the heating mantle is switch OFF and the oil bath is allowed to cool slowly. For every one degree fall of temperature the micro ammeter reading (Is) is noted.

Expt. No.: Date:

Physics Lab Manual


Table .1 Measurement of Saturation current for various temperatures

S. No Temperature Temperature 1000 / T I s Log Is

Unit o C K K-1 X10-6 A A

1

2

3

4

5

6

7

8

9

10

Physics Lab Manual


A graph is plotted taking 1000/T along X axis and log Is along negative Y axis. (Since Is

in the order of micro-ampere, log Is value will come in negative). A straight line obtained as

shown in model graph. By finding the slope of the straight line, the band gap energy can be calculated using the given formula. The sample procedure can be repeated for various constant power supplies (4Volt, 6Volt).

Calculation

Eg = 0.198 x Slope eV

Eg = 0.198 x log Is / (1000/ T) eV

Eg = eV

Result

The band gap energy of the given diode is Eg = _______________ eV

Physics Lab Manual


Fig.20. Viscosity Apparatus

Physics Lab Manual


DETERMINATION OF COEFFICIENT OF VISCOSITY OF A LIQUID BY POISEUILLE’S METHOD

Aim To determine the coefficient of viscosity of a given liquid by Poiseuille’s method. Apparatus Required

• Graduated burette

• Stand with clamp • Capillary tube

• Beaker • Given liquid

• Stop watch

• Meter scale • Rubber tube

• Pinch cock • Traveling microscope

Principle Suppose the liquid is flowing through a uniform capillary tube which is held horizontally, under constant pressure difference between the two ends of the capillary. The flow of liquid through the tube is streamline and the layers which are in contact of the walls of the tube are at rest. The layer along the axis of the tube has the maximum velocity. Volume of the liquid collected for a known time is calculated and the coefficient of viscosity of the liquid is determined. Formula The coefficient of viscosity of a liquid,


ρ Density of the given liquid Kg m-3

g Acceleration due to gravity ms-2

r Radius of the capillary tube m

l Length of the capillary tube m

h which is the pressure head

m

h1

Height from the table to the initial level of liquid in burette. m

h2 Height from the table to the final level of the liquid in burette. m

h0 Height from the table to the axis of the capillary tube m

V Volume of the liquid in 5cc.

m3

24

8

)( −= NsmlV

htgrπρη

021

2h

hh −

+

Expt. No.: Date:

Physics Lab Manual


Table. 1 To calculate time taken for liquid flow

Height of the capillary tube a = ______ X10-2 m Time Taken S. No Burette

Reading Trial 1 Trial 2 Mean Height “b” C = b – a

- cc second second second X10-2m X10-2m

1

2

3

4

5

6

7

8

9

10

Fig.21. Radius of capillary tube

Physics Lab Manual


Procedure Calculation of ‘ht’

The dry burette is fixed on the stand using the clamps as shown in fig.20. The uniform circular bore capillary tube is fixed to the burette using a rubber tube. The capillary tube is arranged horizontal to the table. The stand is used to get uniform flow of a given liquid. A clamp and dry beaker is used to collect the water from the capillary tube for a known interval of time.

The given liquid is poured into the burette. The stop clock is started when the liquid level crosses

0 in burette. The time taken for the liquid to cross every 5cc (starts from 0cc) on the burette say 0, 5, 10, 15, 20, 25 ….50 cc are noted and tabulated. To get accurate readings, the second trial is taken with the same interval of time in burette say 0,5,10,15,20 and 25,………50 cc. Therefore, the time taken for 5 cc of the liquid is determined for the flow time t seconds from the table. The initial height h1 and final height h2 are noted for every 5 cc interval. The length of the capillary tube (l) is measured by using meter scale. It is evident from the table that when the height of the liquid ‘h’ decreases, the time flow of‘t’ increases and hence, the product ‘ht’ remains constant.

Calculation of Radius of the capillary tube

The radius of the capillary (r) is determined using the traveling microscope. The capillary tube is

fixed on the stand and traveling microscope is adjusted to view the inner circle of the capillary tube as shown in Fig.21. The vertical cross wire of the telescope is adjusted to concide with the left edge (V1) of the inner circle. The corresponding MSR and VSC are noted. Similarly, the cross wire adjusted with the right edge (V2) of the inner circle and the readings are noted.

The experiment is repeated using the horizontal cross wire of the telescope and the corresponding readings H1 and H2 are tabulated. The inner diameter of the capillary tube is determined by finding the difference between V1 and V2, H1 and H2. The average value of the diameter is used for the calculation. Calculation of viscosity

Thus, by knowing the values of pressure head h, density of liquid, radius of the capillary tube a,

length of the capillary tube l, and volume of the liquid collected V, the viscosity of the given liquid can be measured using the equation.

Physics Lab Manual


Table. 2 To calculate ‘ht’

Range Time taken to cross 5cc

liquid ‘t’

Initial height

h1

Final height

h2

+=

221 hh

h ht S. No.

Unit seconds X 10-2m X 10-2m X 10-2m X 10-2ms

1 0-5

2 5-10

3 10-15

4 15-20

5 20-25

6 25-30

7 30-35

8 35-40

9 40-45

10 45-50

Mean

Physics Lab Manual


Calculation Density of the given liquid ρ = kgm-3

Acceleration due to gravity g = 9.8 ms-2

Radius of the capillary tube r = x 10 -2m

Length of the capillary tube l = x 10 -2 m

The product of ‘ht’ = x 10 -2 ms

Volume of liquid collected V = x 10 -6 m3

The coefficient of viscosity of a liquid,

Result

The coefficient of viscosity of the given liquid η = ________________ Nsm-2

24

8

)( −= NsmlV

htgrπρη

Physics Lab Manual


DATA OF PHYSICAL CONSTANTS & STANDARD VALUES

S. No Physical Constants Symbol Value in SI Unit

1 Velocity of light c 3 X108 m/s

2 Acceleration due to gravity g 9.8 m/s2

3 Planck’s constant h 6.625X10-34 Js

4 Charge of an electron e 1.6X10-19 C

5 Avogadro number NA 6.023X1026 atoms/ k mole

6 Boltzmann constant kB 1.3X10-23 J/K

7 Rigidity of steel wire n 8.9X1010 Nm-2

8 Rigidity of Brass wire n 3.5X1010 Nm-2

9 Young’s modulus of the wooden beam y 1X1010 Nm-2

10 Young’s modulus of the teak wooden beam y 1.7X1010 Nm-2

11 Co-efficient of Viscosity of water η 0.0008 Nsm-2

12 Co-efficient of Viscosity of coconut oil η 0.0154 Nsm-2

13 Refractive index of crown glass µ 1.5 No unit

14 Wavelength of sodium vapour lamp λ D1= 5890 Å, D2 =5896 Å

λvI 4047 Å

λvII 4078 Å

λB 4358 Å

λBG 4916 Å

λG 5461 Å

λYI 5770 Å

λYII 5791 Å

15 Wavelength of mercury vapour lamp

λR 6234 Å

16 Band gap Eg Germanium= 0.7 eV Silicon = 1.1 eV

gs2165 physics lab manual

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