Electricity

Question 1

You are given current and time, what formula do you use to find the charge

Answer 1

I = Q/t

Question 2

How do you find the voltage when given energy and charges

Answer 2

V=E/Q

Question 3

How do you find resistance when given voltage and current

Answer 3

V=RI

Question 4

What formula relates resistance to length and area

Answer 4

R =Pl/a

Question 5

What formula links power and voltage

Answer 5

P=VI

Question 6

What’s the standard formula to find power?

Answer 6

P=E/t

Question 7

How do you find the total resistance in a Series circuit

Answer 7

R = R1 + R2…

Question 8

How do you find the voltage used for each device in a series circuit

Answer 8

Use ratio method based on the resistance of the devices

Question 9

Will the devices in a series circuit still work if one of them isn’t working?

Answer 9

No

Question 10

Is voltage shared in a series circuit

Answer 10

Yes

Question 11

Is voltage shared in a parallel circuit

Answer 11

No

Question 12

How do you find the total current in a parallel circuit

Answer 12

I = I1 + I2…

Question 13

How do you find total resistance in a parallel circuit

Answer 13

R = 1/R1 + 1/R2…

Question 14

What determines whether a transformer is a step up or step down transformer

Answer 14

The number of coils on the output side - if less, it’s step down, if more, it’s step up

Question 15

State the two formulas used for transformers

Answer 15

VpIp = VsIs
Ns/Np = Vs/Vp

Question 16

Define the left hand rule

Answer 16

Thumb, Force
Pointer, Magnetic Field
Middle finger, Current

Question 17

Define electromagnetic induction

Answer 17

When a current is induced due to the change of a magnetic field close to a solenoid

Question 18

What device uses the left hand rule

Answer 18

Motor

Question 19

What devices use electromagnetic induction

Answer 19

Generator and Transformers

Question 20

In which direction does conventional current flow

Answer 20

From positive to negative

Question 21

what is a resistor

Answer 21

a device used to provide resistance to reduce currents or keep them at a constant level

Question 22

what is a variable resistor or rheostat

Answer 22

used for varying currents in devices to do things such as increasing or decreasing brightness or volume

Question 23

define a thermistor

Answer 23

a device which has high resistance when it’s cold, but low resistance when it’s hot

Question 24

what is a light dependent resistor or LDR

Answer 24

a device with high resistance in the dark but low resistance in the light. used for automatic lights

Question 25

what is a diode

Answer 25

a device with high resistance in one direction but low resistance in the other. it allows current to flow in only one direction, and is used to create d.c.

Question 26

how does the length of a wire affect resistance

Answer 26

as length is increased, resistance increases

Question 27

how does the cross sectional area affect resistance

Answer 27

as the cross sectional area of a wire increases, resistance is decreased

Question 28

how does temperature affect resistance

Answer 28

the higher the temperature of the wire, the higher the resistance

Question 29

how does current affect resistance

Answer 29

as current increases, resistance increases.