A current-carrying conductor placed at right angles to a uniform magnetic field experiences a force of$4.70\times {10}^{-3}N.$ Determine the force on the wire when, separately:

(b) the magne tic flux density is halved

A current-carrying conductor placed at right angles to a uniform magnetic field experiences a force of$4.70\times {10}^{-3}N.$ Determine the force on the wire when, separately:

(c) the length of the wire in the magnetic field is reduced to $40\%$
of its original length.

A copper wire carrying a current of$1.2A$ has $3.0cm$ of its length placed in a uniform magnetic field, as shown.

The force experienced by the wire is $3.8\times {10}^{-3}N$ when the angle between the wire and the magnetic field is$50°.$

(a) Calculate the magnetic flux density.

A copper wire carrying a current of $1.2A$ has $3.0cm$ of its length placed in a uniform magnetic field, as shown.

The force experienced by the wire is$3.8\times {10}^{-3}N$when the angle between
the wire and the magnetic field is$50°.$

(b) State the direction of the force experienced by the wire.

This diagram shows a view from above of two long, parallel strips of aluminium foil,$A$ and $B$, carrying a current downwards into the paper.

(a) On a copy of the diagram, draw the magnetic field around and between the two strips.

This diagram shows a view from above of two long, parallel strips of aluminium foil, A and B, carrying a current downwards into the paper.

(b) State and explain the direction of the forces caused by the current in the strips.

This diagram shows a wire $XY$ that carries a constant direct current. Plotting compass $R$, placed alongside the wire, points due north. Compass $P$ is placed below the wire and compass $Q$ is placed above the wire.

(a) State the direction of the current in the wire.

This diagram shows a wire $XY$ that carries a constant direct current. Plotting compass $R,$ placed alongside the wire, points due north. Compass $P$ is placed below the wire and compass $Q$ is placed above the wire.

(b) State in which direction compass P points.

This diagram shows a wire $XY$ that carries a constant direct current. Plotting compass $R,$ placed alongside the wire, points due north. Compass $P$ is placed below the wire and compass $Q$ is placed above the wire.

 State in which direction compass Q points if the current in
the wire is reversed.