GCSE-CurrentElectricity

Question 1

Total current entering or leaving the battery in a parallel circuit equals the …?… …?… the currents in the branches

Answer 1

sum of

Question 2

The voltage across each branch in a parallel circuit is …??…

Answer 2

the same

Question 3

Equation for total Resistance of a series combination of resistors

Answer 3

Rtotal = R₁ + R₂ + R₃…

Question 4

electrical power equation

Answer 4

P = VI

Question 5

Electric energy equation

Answer 5

E = ItV

Question 6

Equation for total Resistance of a parallel combination of resistors

Answer 6

1/Rtotal = 1/R₁ + 1/R₂ + 1/R₃

Question 7

Alternative equation for total resistance of a parallel combination of 2 resistors only.

Answer 7

Rtotal = product/sum

Question 8

Equation for Ohm’s Law

Answer 8

V = IR

Question 9

Equation to find energy used in kilowatt-hours (kWh)

Answer 9

kWh = power in kW x time in hours

Question 10

The size and direction of direct current (d.c) are both …?

Answer 10

constant

Question 11

The size and direction of alternating current (a.c) both continually…?

Answer 11

change.

Question 12

The unit for power

Answer 12

Watt (W)

Question 13

Equation for total voltage across cells in series

Answer 13

V = V₁+V₂+V₃ + …

Question 14

Equation for the total voltage across components in a series circuit

Answer 14

V = V₁ + V₂+ V₃ + …

Question 15

The current at every point in a series circuit is …?

Answer 15

the same.

Question 16

The equation that links electric current and charge

Answer 16

Q = It

Question 17

The voltage across each branch in a parallel circuit equals the…?

Answer 17

supply voltage

Question 18

As the current through a filament lamp increases the resistance of the filament …?

Answer 18

increases

Question 19

A component which allows electric current to flow through itself only in one direction is called a …?

Answer 19

Diode

Question 20

The unit of electrical resistance is the …?

Answer 20

Ohm (Ω)

Question 21

The unit of electrical current is the …?

Answer 21

Ampere (A)

Question 22

The unit of electrical potential difference is the …?

Answer 22

Volt (V)

Question 23

The yellow and green wire in a three-pin plug is the …?… wire

Answer 23

Earth

Question 24

A good electrical conductor is a good electrical conductor because it possesses …??

Answer 24

free electrons

Question 25

A graph of V against I for a piece of metal wire at constant temperature is a ...?????

Answer 25

straight line through the origin

Question 26

A graph of V against I for a light-bulb filament curves from ...?... to steep.

Answer 26

shallow.

Question 27

Electrical current passing through a metal heats it up because of collisions between free electrons and the ...?... in the metal

Answer 27

ions

Question 28

The total resistance R of two identical resistors r connected in parallel is ...?

Answer 28

r/2

Question 29

If the length of a piece of wire is increased its resistance...?

Answer 29

increases

Question 30

If the diameter of a piece of wire is increased its resistance...?

Answer 30

decreases

Question 31

The Earth wire and ...?... together protect the user from electric shock and the equipment from damage.

Answer 31

fuse

Question 32

General definition of power

Answer 32

P = E/t

Question 33

What colour is the live wire in a plug?

Answer 33

Brown

Question 34

What colour is the neutral wire in a plug?

Answer 34

Blue

Question 35

To which pin in a plug should the Earth wire be connected?

Answer 35

The top pin

Question 36

In a plug, which wire must be connected to the pin that has a fuse attached?

Answer 36

The live wire (brown).

Question 37

What is the function of the live wire in a circuit?

Answer 37

It carries current to the device.

Question 38

What is the function of the neutral wire in a circuit?

Answer 38

It carries current from the device.

Question 39

On what side of any device must any switch and any fuse be connected?

Answer 39

The live side.

Question 40

Equation linking resistance and length for a metallic wire at constant temperature.

Answer 40

R=kL where k is a constant.

Question 41

How to find the total resistance of a combination including parallel and series sections.

Answer 41

1. Find the resistance of each parallel section. 2. Add these resistance values to those of the resistors in series.

Question 42

The gradient of a V against I graph at any point gives the ...?... of the component at that current value.

Answer 42

resistance.

Question 43

Ohm's Law in words.

Answer 43

For any metallic conductor at constant temperature, the applied voltage is directly proportional to the current flowing through the conductor.

Question 44

How to calculate the correct rating for a fuse.

Answer 44

1. Calculate the normal current for the device using P=VI 2. Choose the smallest fuse rating higher than the normal current.