Physics Homework [Electricity 2]

Question 1

If the potential difference across a component with a fixed resistance is increased, describe the effect on the current.

Answer 1

The current increases.

Question 2

State the standard units for resistance.

Answer 2

Ohms

Question 3

To find the resistance of a component, identify the two variables that need to be measured experimentally.

Answer 3

Potential difference across the component and current flowing through it.

Question 4

When investigating how the length of a wire affects the resistance of the wire, name the dependent variable.

Answer 4

Resistance of the wire.

Question 5

When measuring the resistance of a piece of wire, explain why the potential difference should be kept small.

Answer 5

So there is a small current and the wire does not heat up as much.

Question 6

If a circuit is closed, explain how electrical charges can be made to flow.

Answer 6

By including a source of potential difference such as a cell or battery.

Question 7

Explain which of these diagrams shows a voltmeter connected correctly to measure the potential difference across the bulb.

Answer 7

B, in parallel.

Question 8

Name the charged subatomic particles that can flow in metals.

Answer 8

Electrons.

Question 9

What does LDR stand for?

Answer 9

Light-dependent resistor.

Question 10

In the circuit diagram, compare the current at X with the current at Y.

Answer 10

They are the same.

Question 11

When investigating how the length of a wire affects the resistance of the wire, name the independent variable.

Answer 11

Length of the wire.

Question 12

In symbols, state the equation that links charge flow, current and time.

Answer 12

Q = I x t

Question 13

Name the components labelled F to J.

Answer 13

Fixed resistor, Variable resistor, Light Emitting Diode, Filament Bulb, Fuse

Question 14

In terms of mathematics, define rate.

Answer 14

Divided by time (/ t)

Question 15

In symbols, state the equation that links potential difference, current and resistance.

Answer 15

V = I x R

Question 16

Name the components labelled A to E.

Answer 16

Open switch, closed switch, Cell, Battery, Diode

Question 17

State the standard units for charge.

Answer 17

Coulombs (C)

Question 18

State the standard units for current.

Answer 18

Amps (A)

Question 19

State the standard units for potential difference.

Answer 19

Volts (V)

Question 20

Define the size of an electrical current in terms of electrical charge.

Answer 20

The rate of flow of electrical charge.