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CAIE A-Level Physics AS 9.1 Electric Current Questions

Practise relating current to charge flow, Q = It, charge quantisation and I = Anvq, checking carriers, units and conductor data.

Syllabus
2028–2030
Course
Physics 9702
Level
AS

Exam points

  • interpret electric current as flow of charge carriers and use Q = It to calculate charge, current, time or carrier count
  • apply I = Anvq to analyse carrier density, drift speed, cross-sectional area and charge in a current-carrying conductor
  • use quantisation of charge to judge possible charge values and relate charge to elementary carriers

Covered syllabus points

9.1.1—An electric current is a flow of charge carriers9.1.2—The charge on charge carriers is quantised9.1.3—Q = It9.1.4—Use, for a current-carrying conductor, the expression I = Anvq

Question 1

[Maximum number: 1]

What could not be used to create an electric current?

A

alpha-particles

B

beta-particles

C

neutrons

D

protons

Question 2

[Maximum number: 1]

An electric current is formed by moving charge carriers.
What is not a possible charge on a charge carrier?

A

−4.8×10−19C-4.8 \times 10^{-19} \mathrm{C}

B

−2.4×10−19C-2.4 \times 10^{-19} \mathrm{C}

C

+1.6×10−19C+1.6 \times 10^{-19} \mathrm{C}

D

+3.2×10−19C+3.2 \times 10^{-19} \mathrm{C}

Question 3

[Maximum number: 1]

A radioactive source produces a beam of α\alpha-particles in a vacuum. The average current caused by the α\alpha-particles in the beam is 1.5×10−9 A1.5 \times 10^{-9} \mathrm{~A}.

The beam is incident on a metal target.
What is the average number of α\alpha-particles hitting the metal target in a time of 3.0 s ?

A

4.7×1094.7 \times 10^{9}

B

9.4×1099.4 \times 10^{9}

C

1.4×10101.4 \times 10^{10}

D

2.8×10102.8 \times 10^{10}

Question 4

[Maximum number: 1]

A cylindrical wire has cross-sectional area A and number density of free electrons n. The wire has current I and the free electrons have average drift speed v.

A second cylindrical wire has cross-sectional area 0.5 A and number density of free electrons 2 n. In this wire, the free electrons have average drift speed 2 v.

What is the current in the second wire?

A

0.5 I

B

I

C

2 I

D

4 I

All question bank results loaded