Topic 10 🔋🎡

Question 1

If there is a potential difference in the circuit, there will also be a…

Answer 1

Current

Question 2

How is current defined?

Answer 2

As the rate of flow of charge (or electrons) around a circuit

Question 3

What are the units of charge?

Answer 3

Coulombs, C

Question 4

What are the two ways that a component can be connected in a circuit?

Answer 4

1. series (same loop)
2. Parallel (adjacent loop)

Question 5

Voltage is also know as…

Answer 5

Potential difference

Question 6

How does potential different across two components vary when connected in series?

Answer 6

In a series circuit the total PD is shared between each component.

Question 7

How does the potential difference across two components vary when connected in parallel?

Answer 7

In a parallel circuit the PD across each component is the same.

Question 8

If two resistors are connected in parallel, what can be said about their combined total resistance?

Answer 8

Their total resistance is less than the smallest of the two individual resistances.

Question 9

If two resistors are connected in series what can be said about their total resistance?

Answer 9

Their total combined resistance is equal to the sum of the two individual resistances.

Question 10

When must a voltmeter be placed in a circuit?

Answer 10

In parallel with the component that is being measured.

Question 11

Give an equation relating to PD with energy transferred and charge.

Answer 11

Potential difference (V) = energy transferred (J) / charge (C)

V=E/Q

Question 12

A volt can be described as a…

Answer 12

Joule per coulomb

Question 13

What is an electric current?

Answer 13

The rate of flow of charge.

Question 14

State the equation linking charge, current and time. Give the units for the quantities involved.

Answer 14

Q = I x t

Charge (Coulombs), Current (Amps), Time (Seconds)

Question 15

What can said about the value of current at any point in a single closed loop?

Answer 15

Current is the same at all points in a closed loop.

Question 16

What two facets does the current in a circuit depend on?

Answer 16

1. PD (V)
2. Resistance (Ohms)

Question 17

What equation should be used to calculate potential difference of current resistance known? State the units for all three quantities.

Answer 17

V = I x R

Potential Difference (V), Current (A), Resistance (Ohms)

Question 18

What is an ammeter and where must it be connected in a circuit?

Answer 18

An ammeter measures current. It is placed in series with the component it is required to measure.

Question 19

What happens when current reaches a junction in the circuit?

Answer 19

Current is conserved; total current remains the same, and it’s split between the two branches

Question 20

How does resistance affect current in a circuit?

Answer 20

As the total resistance of a circuit increases, the current flowing through the circuit decreases.

Question 21

How can the current circuit be varied?

Answer 21

Using a variable resistor.

Question 22

Give the equation linking current with resistance

Answer 22

p.d (V) = current (A) x resistance (Ohms)

V = I x R

Question 23

How is total resistance affected by two resistors in series?

Answer 23

Total resistance increases; it is equal to the sum of the two resistors.

Question 24

How is the total resistance affected by two resistors in parallel?

Answer 24

The total resistance decreases; it is less than the resistance of the resistor with the lowest resistance

Question 25

What is an Ohmic Conductor? State the conditions required.

Answer 25

• A conductor for which current current and potential difference directly proportional.
• Resistance remains constant as current changes.
• Temperature must be constant.

Question 26

List four components for which resistance is not constant as current changes.

Answer 26

1. Filament Lamps
2. Diodes
3. Thermistors
4. Light Dependant Resistors (LDR’s)