subject test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (mcq)...

8
Kreatryx Subject Test Electrical and Electronic Measurements www.kreatryx.com

Upload: others

Post on 17-May-2020

41 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in

Kreatryx

Subject Test

Electrical and Electronic

Measurements

www.kreatryx.com

Page 2: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in

1

KST- General Instructions during Examination

1. Total Duration of KST is 60 minutes.

2. The question paper consists of 2 parts. Questions 1-10 carry one mark each and Question 11-

20 carry 2 marks each.

3. The question paper may consist of questions of Multiple Choice Type (MCQ) and

Numerical Answer Type.

4. Multiple choice type questions will have four choices against A, B, C, D, out of which

only ONE is the correct answer.

5. All questions that are not attempted will result in zero marks. However, wrong

answers for multiple choice type questions (MCQ) will result in NEGATIVE marks.

For all MCQ questions a wrong answer will result in deduction of 𝟏/𝟑 marks for a 1-mark

question and 𝟐/𝟑 marks for a 2-mark question.

6. There is NO NEGATIVE MARKING for questions of NUMERICAL ANSWER TYPE.

7. Non-programmable type Calculator is allowed. Charts, graph sheets, and

mathematical tables are NOT allowed during the Examination.

Page 3: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in

2

Q.1 The total current I=I1+I2 in a circuit is measured whereas 1 2I   150  1A , I  1  50 2A the

limits of error are given as standard deviations. I is measured as

(A) (300 ± 1.24)A (B) (300 ± 1.73)A

(C) (300 ± 2)A (D) (300 ± 2.24)A

Q.2 An ac bridge shown below has the following specifications 1

C 0.5 F and 1

R 1k ,

3

C 0.5 F . If the supply frequency is 1 kHz, determine the dissipation factor.

(A) 2.142

(B) 3.142

(C) 4.142

(D) 5.142

Q.3 A length of cable is tested for insulation resistance by loss of charges method. An

electrostatic voltmeter of infinite resistance is connected between the cable conductor and

earth, forming there with a joint capacitance of 500pF. If is observed that after charging it,

the voltage falls from 250 V to 92 V in 1 minute. The insulation resistance of the cable is

10(A) 2 10 (B) 100,000M Ω 11(C) 1.2 10 7(D) 86.8 10

Q.4 To check the distributed capacitance of a coil, it is resonated at 10 MHz with 120pF and

then is resonated at 15 MHz with 40 pF. What is its equivalent distributed capacitance?

(A) 12pF (B) 18pF (C) 24 pF (D) 30pF

Q.5 A

14

2 digit voltmeter is used to measure the voltage value of 0.3861 V on a 1 range. It

would be display

(A) 0 .3 8 6 1 (B) 0 0 .3 8 6

(C) 0 0 0 .3 8 (D) .3 8 6 1 0

Q.6 A voltmeter reading 80 V on its 100V range and an ammeter reading 80 mA on its 150 mA

range, are used to determine the power dissipated in a resistor. Both these instruments are

guaranteed to be accurate within ±2%, at full scale deflection. The limiting error in the

measurement of the power dissipation is

(A) 3.25% (B) 4.25% (C) 5.25% (D) 6.25%

Page 4: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in

3

Q.7 A set of independent current measurement taken by four observers was recorded as :

115.02 mA, 115.11,A, 115.08mA and 115.04 mA. What is the average range of error?

(A) 0. 045 mA (B) 0.04 mA (C) 0.0425 mA (D) 0.5 mA

Q.8 In a thermocouple based instrument, if 20% harmonic is present then error in the current

reading is

(A) 0% (B) 2% (C) 4% (D) 5%

Q.9 Calculate the value of the multiplier resistor for a 10 V rms range on the voltmeter as

shown in the figure given below.

(A) 2.3 k Ω

(B) 3.3 k Ω

(C) 4.3 k Ω

(D) 5.3 k Ω

Q.10 A voltmeter, having a sensitivity of 2k Ω/V, connected across an unknown resistance in

series with a milliammeter, reads 100 V on 150 V scale. If the milliammeter reads 10 mA, the

error due to loading effect of voltmeter would be – y% , then the value of y is __________.

Q.11 A coil with a resistance of 3 Ω is connected to the terminals of a Q meter. Resonance

occurs at an oscillator frequency of 5 MHz with a capacitance of 100 pF. If –x% is the error

introduced by the insertion resistance Rsh,=0.1 Ω then the value of x is ___________.

Q.12 Calculate the constants of a shunt to extend the range of 0 – 5 A moving iron ammeter to

0 – 50 A. The instrument constants are R = 0.09 Ω and L = 90µH If the shunt is made non-

inductive and the combination is correct on d.c. find the full scale error at 50 Hz.

(A) 3.8% high (B)2.8%low (C) 2.8% high (d)3.8%low

Q.13 The coil of a 300 V moving iron voltmeter has a resistance of 500 W and an inductance of

0.8H.The instrument reads correctly at 50Hz. A.C. supply and takes 100 mA at full scale

deflection. What is the percentage error in the instrument reading, when it is connected to 200V

d.c.supply.

(A)200.6 V (B)205.6V (C) 210 V (D)212.2V

Page 5: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in

4

Q.14 A single-phase load is connected between R and Y terminals of 415 V, symmetrical 3-

phase, 4 wire systems with phase sequence RYB. A wattmeter is connected in the system as

shown in figure below. The power factor of the load is 0.8 lagging. The wattmeter will read

(A)–197.23 watt

(B)–248.58watt

(C)–295.29 watt

(D)–298.23 watt

Q.15 An energy meter rated as 5A, 230 V makes 500 revolutions per kWh. If in a test at full load

unity power factor, it makes 5 revolutions in 30 seconds. Then which of the following statement

is true?

(A) The meter runs faster and error is 4.16%

(B) The meter runs faster and error is 4.35%

(C) The meter runs slower and error is 4.16%

(D) The meter runs slower and error is 4.35%

Q.16 Figure shown below is the circuit of a capacitance comparison bridge. If R1 = 20 Ω

R2=30 Ω R3 = 25 and C3 = 10 pF than the value of Rx and Cx respectively are.

(a) 27.5 , 26/3 pF

(b) 30.5 , 28/3 pF

(c) 35.5 , 22/3 pF

(d) 37.5 , 20/3 pF

Q.17 Figure gives parameter values of an AC bridge at balance when supply frequency is

1500Hz. Find Zx assuming it to be a resistance Rx in series with an inductance or capacitance

and choose the correct option

(A) 210 F

(B) 210

F

(C) 210

H

(D) 210

Page 6: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in

5

Q.18 A CRO is used to measure the voltage as shown below in the diagram. CRO probe has the

impedance of 600 k with a capacitance in parallel of a value of 20 pF. The reading of CRO will

be _________ V.

Q.19 For an electrodynamometer ammeter. The mutual inductance M varies with deflection ϴ

(ϴ is in degree) as M = -6cos(ϴ +45o) mH. For a direct current of 50 mA corresponding to a

deflection of 600, the deflecting torque will be _______µNm.

Q.20 A current of i 0.5 0.3 sin t 0.2 sin 2 t A is passed through the circuit shown in

figure given below. _______ ampere is the sum of readings of each instrument. 6( = 10 rad/s)

Page 7: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in

6

Power Systems KST

Answer Key

1 2 3 4 5 6 7 8 9 10

C C A B 4 C B B C D

11 12 13 14 15 16 17 18 19 20

D C A C C D D 16.8-17.7 B C

Page 8: Subject Test - vsmadhukar.files.wordpress.com...answers for multiple choice type questions (MCQ) will result in NEGATIVE marks. For all MCQ questions a wrong answer will result in