Physics 9702 · AS & A Level

Force on a current-carrying conductor

28 practice questions on Force on a current-carrying conductor, with worked solutions and instant marking.

As shown in Fig. 8.1, a horseshoe magnet is resting on a top pan balance. A rigid copper wire is secured between the magnet’s poles, with the wire clamped at ends $A$ and $B$.

Feb/March 2019

State what is meant by a magnetic field.

Feb/March 2020

Two long straight wires P and Q are arranged parallel to one another, as shown in Fig. 8.1. Each wire carries a current in the direction indicated. The magnetic field-line pattern in a plane perpendicular to wire P caused by the current in that wire is also shown.

Feb/March 2021

Within a uniform magnetic field, the flux density $B$ is constant. A straight wire of fixed length carries a current $I$ at an angle $\theta$ to the magnetic field, as shown in Fig. 6.1.

May/June 2010

In a uniform magnetic field, the flux density $B$ is constant. Figure 6.1 shows a straight wire of fixed length carrying a current $I$ at an angle $\theta$ to the magnetic field.

May/June 2010

Two long, straight, parallel copper wires A and B are held vertically in clamps. The wires pass through holes in a horizontal card labelled PQRS, as shown in Fig. 7.1.

May/June 2012

Define the tesla as a unit.

May/June 2012

As shown in Fig. 7.1, two long, straight copper wires A and B are held vertically and parallel to each other. They pass through holes in a horizontal sheet of card PQRS.

May/June 2012

As illustrated in Fig. 9.1, a rigid copper wire is positioned horizontally between the pole pieces of two magnets. Each pole piece has width $8.5\,\text{cm}$. The magnetic flux density $B$ is uniform in the space between the magnet poles, with value $3.7\,\text{mT}$, and it is zero beyond this area. The angle between the wire and the magnetic field direction is $\theta$. The current in the wire follows the direction shown in Fig. 9.1.

May/June 2018

A stiff copper wire is positioned horizontally between the pole pieces of two magnets, as illustrated in Fig. 9.1. Each pole piece has a width of $8.5\text{ cm}$. In the space between the magnet poles, the uniform magnetic flux density $B$ is $3.7\text{ mT}$, while it is zero elsewhere. The angle between the wire and the direction of the magnetic field is $\theta$. The current in the wire flows in the direction indicated in Fig. 9.1.

May/June 2018

Define the tesla unit.

May/June 2020

State the meaning of the tesla.

May/June 2020

State two cases in which a charged particle in a magnetic field does not feel a force.

May/June 2021

State the two conditions that must be met for a copper wire placed in a magnetic field to experience a magnetic force.

May/June 2022

State the meaning of a magnetic field.

May/June 2023

State what the term magnetic field means.

May/June 2023

As shown in Fig. 6.1, a rectangular wire coil PQRS can turn freely about axis XY. Side QR is 5.4\,\text{cm} long, side PQ is 2.5\,\text{cm} wide, and the coil has 190 turns of wire. The coil’s plane makes an angle \theta with a uniform magnetic field of flux density 5.2 \times 10^{-3}\,\text{T}. Axis XY is perpendicular to the field. The current in the coil is 1.2\,\text{A}.

May/June 2025

A rigid straight copper wire XY is clamped in place within a uniform magnetic field of flux density $2.6 \times 10^{-3}\,\text{T}$, as illustrated in Fig. 6.1. The wire XY is $4.7\,\text{cm}$ long and is inclined at an angle of $34^\circ$ to the magnetic field.

Oct/Nov 2014

A rigid straight copper wire XY is secured in place within a uniform magnetic field of flux density $2.6 \times 10^{-3}\,\text{T}$, as shown in Fig. 6.1. The wire XY is $4.7\,\text{cm}$ long and is inclined at an angle of $34^\circ$ to the magnetic field.

Oct/Nov 2014

As shown in Fig. 9.1, a stiff wire is supported horizontally between the poles of a magnet. When a constant current of $6.0\,\text{A}$ flows through the wire, the magnet experiences an extra downward force of $0.080\,\text{N}$.

Oct/Nov 2016

State what is meant by magnetic flux density.

Oct/Nov 2018

A long, straight, vertical wire A carries a current upwards. It passes through the centre of a horizontal card, as shown in Fig. 10.1. The card is seen from above in Fig. 10.2.

Oct/Nov 2020

Define the tesla in words.

Oct/Nov 2021

As shown in Fig. 8.1, two long, straight, parallel wires P and Q have currents directed into the plane of the paper. The current in P is $I$ and the current in Q is $2I$.

Oct/Nov 2021

Define the unit tesla.

Oct/Nov 2021

Define the term magnetic flux density.

Oct/Nov 2022

Define the term magnetic flux density.

Oct/Nov 2024

Define the term magnetic flux density.

Oct/Nov 2024