Equations

Question 1

Current

Answer 1

Current = Charge/Time
I = Q/t

Question 2

Resistance

Answer 2

Resistance = Voltage/Current
R = V/

Question 3

Voltage in terms of charge and energy

Answer 3

Voltage = Energy/Charge
V = E/Q

Question 4

Power in terms of current and voltage

Answer 4

Power = Current x Voltage
P = IV

Question 5

Power in terms of current and resistance

Answer 5

Power = Current^2 x Resistance 
P = I^2R

Question 6

Energy transfer

Answer 6

Energy transfer = power x time

E = VIt

Question 7

Relationship between number of turns on the primary and secondary coil and the voltages of each in transformers

Answer 7

Vp/Vs = np/ns

Question 8

Relationship between power at 100% efficiency in transformers

Answer 8

VpIp = VsIs

Question 9

Speed

Answer 9

Speed = Distance/Time

Question 10

Velocity

Answer 10

Velocity = Change in Displacement/Time

Question 11

Acceleration

Answer 11

Acceleration = Change in Velocity/Time

Question 12

Average Speed

Answer 12

Average Speed = Total Distance/Total Time

Question 13

Velocity^2 (SUVAT)

Answer 13

v^2 = u^2 + 2as

Question 14

Energy stored in a stretched spring/strain energy in terms of force

Answer 14

E = 1/2Fx

Question 15

Energy stored in a stretched spring/strain energy in terms of the spring constant

Answer 15

E = 1/2kx^2

Question 16

Newton’s Second Law

Answer 16

Force = Mass x Acceleration
F = ma

Question 17

Weight

Answer 17

Weight = Mass x Gravitational Constant 
W = mg

Question 18

Momentum

Answer 18

Momentum = Mass x Velocity
p = mv

Question 19

Force in terms of momentum

Answer 19

Force = Rate of Change in Momentum

Question 20

Work

Answer 20

Work = Force x Distance Moved in Direction of Force

Question 21

Gravitational Potential Energy

Answer 21

Gravitational Potential Energy = Mass x Gravitational Constant x Change in Height
GPE = mgh

Question 22

Kinetic Energy

Answer 22

Kinetic Energy = 1/2 x Mass x Velocity^2

KE = 1/2mv^2

Question 23

Power in terms of energy transfer

Answer 23

Power = Energy Transfer/Time

Question 24

Percentage efficiency of energy

Answer 24

Percentage Energy = (Useful Output/Total Input) x 100

Question 25

Specific Heat Capacity

Answer 25

Specific Heat Capacity = Thermal Energy/(Mass x Temperature Change)

Question 26

Relationship between pressure on a gas and volume at a constant temperature

Answer 26

PV = constant

Question 27

Density

Answer 27

``` Density = Mass/Volume p = m/v ```

Question 28

Pressure with force

Answer 28

Pressure = Force/Area

Question 29

Hydrostatic Pressure

Answer 29

Hydrostatic Pressure = Height(Depth) of Liquid x Pressure x Gravitational Constant

Question 30

Frequency of a wave

Answer 30

``` Frequency = 1/Time Period f = 1/T ```

Question 31

Wave speed in terms of distance and time

Answer 31

Wave Speed = Distance/Time

Question 32

Wave speed in terms of frequency and wavelength

Answer 32

Wave Speed = Frequency x Wavelength | V = f(lambda)

Question 33

Relationship between angle of incidence and angle of reflection

Answer 33

Angle of Incidence = Angle of Reflection

Question 34

Moment

Answer 34

Moment = Force x Perpendicular Distance from the Point to the Line of Action of the Force

Question 35

Velocity (SUVAT)

Answer 35

v = u + at

Question 36

Distance (SUVAT with t^2)

Answer 36

s = ut + ½(at^2)

Question 37

Distance (SUVAT with u and v)

Answer 37

s = ½(u + v)t

Question 38

Power in terms of force and velocity

Answer 38

Power = Force x Velocity

Question 39

Impulse

Answer 39

Impulse = Force x Change in Time

Question 40

Efficiency of energy transfer

Answer 40

Efficiency = (Useful Energy Transfer/Total Energy Input) x 100

Question 41

Pressure with normal force

Answer 41

Pressure = Normal Force/Area

Question 42

Spring constant

Answer 42

Spring Constant = Force/Extension

Question 43

Young modulus

Answer 43

Young Modulus = Stress/Strain

Question 44

Stress

Answer 44

Stress = Force/Cross-Sectional Area

Question 45

Strain

Answer 45

Strain = Extension/Un-stretched Length

Question 46

Refractive index in terms of wave speed

Answer 46

Refractive Index = Speed1/Speed2

Question 47

Refractive index in terms of angle

Answer 47

Refractive Index = sin(theta1)/sin(theta2)

Question 48

Refractive index in terms of the critical angle

Answer 48

Refractive Index = 1/sin(Critical Angle)

Question 49

Charge in terms of current and time

Answer 49

Charge = Current x Time

Question 50

Potential difference in terms of work done and charge

Answer 50

Potential Difference = Work Done/Charge

Question 51

Voltage in terms of current and resistance

Answer 51

Voltage = Current x Resistance

Question 52

Power in terms of voltage and resistance

Answer 52

Power = Voltage^2/Resistance

Question 53

Resistivity

Answer 53

Resistivity = Resistance x (Cross-Sectional Area/Length)

Question 54

Relationship between voltage in and voltage out and resistance 1 and resistance 2 in a potential divider circuit

Answer 54

Vout/Vin = R1/(R1 + R2)

Question 55

Relationship between V1 and V2 and R1 and R2 in a potential divider circuit

Answer 55

V1/V2 = R1/R2