Electromagnetism Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Physics — Higher

What is a current-carrying solenoid?

A coil of wire whose turns produce a combined magnetic field.

What is the magnetic field pattern outside a solenoid?

Like a bar magnet’s field, the field lines curve from the north pole to the south pole.

What is the magnetic field like inside a long solenoid?

It is approximately uniform, with nearly parallel field lines directed from south to north.

How can the right-hand rule identify a solenoid’s north pole?

Curl the fingers in the direction of conventional current around the turns; the thumb points towards the north pole.

What happens to a solenoid’s magnetic field when its current is reversed?

The field reverses direction and the north and south poles swap.

How can a plotting compass be used to map a current-produced magnetic field?

Close the circuit and place the compass at successive positions, marking the direction of its north-seeking end. Join the marks to form field lines and add arrows for their direction.

How is a straight wire positioned to map its magnetic field with a compass?

Pass the wire through a horizontal card and connect it to a circuit.

How should a solenoid be positioned for magnetic field mapping with a compass?

Arrange the coil so that the compass can reach points around it.

What can iron filings show about a magnetic field that they cannot show about its direction?

They show the shape of the field pattern, but not its direction. A compass is needed to establish direction.

What happens to the direction of a current-produced magnetic field when the current is reversed?

The field direction reverses.

Why should the current be switched off between magnetic field measurements?

To limit heating.