3. s.i units and formula
TRANSCRIPT
202/1 – Know the principles of electricity
Outcome 1.4/1.5 – Standard form and formula
transposition
Unit 202 Principles of electrical science
1.2 Identify sources of an electromotive force MAGNETIC CHEMICAL THERMAL
1.3 Describe the effects of an electric current
Last session
Unit 202 Principles of electrical science
Unit 202 summative assessment June 2015 (TBC)
1.4 Identify SI Units for various electrical quantities Current, potential, resistance, resistivity, temperature, force, magnetic flux, magnetic flux density, period, frequency, power, energy, time, length, area, mass, weight.
1.5 Transpose basic formulae.
This session
Current
Potential
Resistance
Current, potential, resistance
Formula (triangle)
Current, potential, resistance
Current
Potential
power
Current, potential, power
Formula (triangle)
Current, potential, power
Resistivity
Area
Length
Resistivity, length and area
Formula
Resistivity, length and area
Resistivity of common materials
period, frequency and time
period, frequency and time
Formula
magnetic flux, magnetic flux density and area
magnetic flux, magnetic flux density and area
Magnetic flux is how strong a magnet is.
Magnetic flux is given the symbol Φ and is measured in units called Webers (Wb).
magnetic flux, magnetic flux density and area
Magnetic flux density is how much magnetism there is in an area
Magnetic flux density is given the symbol B and is measured in units called Teslas (T).
magnetic flux, magnetic flux density and area
FormulaFlux (Φ) = Flux density (B) x area (A)
Φ = BA
Transpose
Mass and weight
What is the difference between mass and weight?
Mass = 80 kg Mass = 80 kg
Weight = 0 Weight = 80 × gravity
Mass and weight
Gravity on earth = 9.81m/s²
Gravity on moon = 1.62m/s²
Mass and weight
Formula
Weight (N) = mass (kg) x gravity (9.81)
Transpose
Mass and weight
Earth Moon Mercury Venus Mars Pluto
Surface Gravity(compared to
Earth)1 0.17 0.38 0.90 0.38 0.06
How muchyou can lift
10 kg
60 kg 30 kg 10 kg 30 kg 170 kg
How highyou can jump
20 cm
120 cm
53 cm 22 cm 53 cm 340 cm
How long it takes to fall back to the
ground0.4 s 2.4 s 1.1 s 0.4 s 1.1 s 6.8 s
How far youcan kick a ball
20 m 120 m 53 m 22m 53 m 340 m
ForceMeasured in Newtons (N)
Distance Measured in metres (M)
EnergySame as work done measured in Joules(J) symbol W
Force, distance and energy
Formula
transpose
Force, distance and energy
1.4 Identify SI Units for various electrical quantities Current, potential, resistance, resistivity, temperature, mass, force, magnetic flux, magnetic flux density, period, frequency, power, energy, time, length, area, mass, weight.
1.5 Transpose basic formulae.
Consolidation
Outcome 1 formative assessment
Next session