Electromagnetic induction

A magnet is positioned close to a solenoid which is connected to a sensitive centre-zero ammeter. The magnet is then pushed in the direction of the solenoid. It speeds up, then travels with constant speed, then slows down and comes to rest inside the solenoid. At what point does the ammeter reading become zero?

May/June 2015

A teacher pushes a magnet in and out of a coil of wire, as shown, to show electromagnetic induction. Which statement is correct?

May/June 2015

Fig. 7.1 shows a straightforward setup for demonstrating electromagnetic induction. The coil is joined to two light-emitting diodes (LEDs). The magnet moves in and then out of the coil.

May/June 2015

Describe how you would show that an induced current is created in a coil of wire. Sketch and label the apparatus arrangement.

May/June 2016

The N-pole of a magnet is pushed into a solenoid, producing an e.m.f. by induction. What would cause the induced e.m.f. to increase?

May/June 2017

Fig. 7.1 illustrates a metal rod positioned between the poles of a magnet.

May/June 2017

A computer hard disk has a layer made of magnetic material.

May/June 2018

Fig. 7.1 shows a section of a torch. No battery is fitted inside the torch. When the torch is shaken, the magnet moves back and forth through the coil.

May/June 2019

In an alternating current (a.c.) generator, a magnet turns close to a coil of wire. The induced electromotive force (e.m.f.) across the coil is shown on an oscilloscope screen. Which trace is obtained when the magnet slows down?

May/June 2021

A trolley fitted with a strong magnet moves down a ramp at a steady speed. As it goes through a coil, as shown, an electromotive force (e.m.f.) is induced in the coil. A graph showing e.m.f. against time is drawn. The investigation is carried out again using different coils and a steeper ramp. On the steeper ramp, the trolley travels at a larger steady speed. Which graph is obtained with the coil having the fewest turns and the steepest ramp? Every graph is on the same scale.

May/June 2021

A student raises a metal bar upwards through the space between the poles of a magnet, as illustrated in Fig. 6.1. Fig. 6.1 illustrates a metal bar moving upwards between the N and S poles of a magnet, with an ammeter connected. As the bar moves, the connected ammeter shows a small positive reading.

May/June 2021

When the magnet is pushed into the coil of wire as illustrated, the sensitive ammeter shows a small positive reading. Which change must make the reading larger?

May/June 2022

When a magnet is pushed into the coil of wire shown, the sensitive ammeter gives a small positive reading. Which change would have to make the reading larger?

May/June 2022

As wire XY is moved downwards between the poles of a magnet that is not moving, an e.m.f. is induced across X and Y. Which action would induce an e.m.f. across X and Y in the opposite direction?

May/June 2023

A coil of wire placed above a magnet is released. As the coil moves downward over the magnet, an e.m.f. is induced across the coil. Which factor does not influence the magnitude of the e.m.f. induced across the coil?

May/June 2023

Fig. 9.1 depicts a basic a.c. generator.

May/June 2023

A plotting compass contains a needle. That needle is a tiny magnet that can turn around its centre. Fig. 7.1 shows the plotting compass positioned near a bar magnet. A point P is marked. Fig. 7.2 shows the apparatus used by a student to generate an alternating current (a.c.). The apparatus contains a magnet, a coil and a centre-zero ammeter. The magnet is pushed into and pulled out of the coil.

May/June 2024

A square coil is situated in a horizontal uniform magnetic field. The coil’s plane is at right angles to the magnetic field. The coil is then turned about an axis passing through point $P$ at a constant rate. The coil turns through $180^{\circ}$. Which diagram shows how the electromotive force (e.m.f.) induced in the coil changes as it turns through $180^{\circ}$?

May/June 2025

Fig. 10.1 displays a solenoid (long coil) X linked in series with a battery, a switch S and a variable resistor (rheostat). Switch S is closed, so the current in the solenoid produces a magnetic field.

Oct/Nov 2015

A thin wire with plastic insulation is wound into a solenoid (long coil). The solenoid is joined to a sensitive ammeter. Fig. 10.1 shows the N-pole of a steel magnet positioned beside the solenoid. Points X and Y are located on the axis of the solenoid.

Oct/Nov 2015

A magnet oscillates vertically above a coil of wire. The lower end of the magnet moves up and down between P and R. At which position is the lower end of the magnet when there is no induced electromotive force (e.m.f.) in the coil?

Oct/Nov 2016

A magnet is moved vertically up and down above a wire coil. The lower end of the magnet travels up and down between P and R. At what position is the lower end of the magnet when no induced electromotive force (e.m.f.) is produced in the coil?

Oct/Nov 2016

The diagram illustrates a wire XY positioned between the poles of a magnet. Each end of the wire is attached to a sensitive ammeter. The wire is then moved, and a reading is recorded. In what direction is the wire moved?

Oct/Nov 2017

The metals listed below are used in many different applications. aluminium copper iron silver steel

Oct/Nov 2017

Fig. 7.1 illustrates the arrangement of a transformer. A lamp is attached to the secondary coil.

Oct/Nov 2018

A small electric component in a circuit must be shielded from a strong external magnetic field. Describe how this is carried out and state any material used.

Oct/Nov 2019

What converts kinetic (movement) energy into electrical energy?

Oct/Nov 2020

EITHER: Fig. 7.1 depicts a solenoid joined to an ammeter. The S-pole of a permanent magnet is moved into the left-hand end of the solenoid. The ammeter shows that a small positive current flows in the circuit. OR: Fig. 7.2 gives the symbol for a logic gate and its truth table.

Oct/Nov 2021

A magnet passes through a coil of wire at constant speed. The coil is connected to an oscilloscope. The diagram shows the trace formed on the screen. The experiment is then altered and a different trace is produced. Which statement explains why the new trace differs from the original trace?

Oct/Nov 2023

A bar magnet is released so that it falls through a vertical solenoid, which is connected to a sensitive ammeter. An induced current flows in the solenoid, and the solenoid acts as an electromagnet. Which row states the polarity of end Y of the solenoid and the force between the solenoid and the bar magnet as the bar magnet emerges from the solenoid?

Oct/Nov 2023

Fig. 8.1 illustrates a permanent magnet attached to one end of an unstretched spring and kept stationary just above a solenoid. The solenoid is linked to a sensitive ammeter.

Oct/Nov 2023

A magnet passes through a coil of wire, as shown. Magnetic poles are formed at the two ends of the coil when the magnet goes into the coil and again when the magnet comes out of the coil. Which pole is induced at P as the magnet enters the coil, and which pole is induced at Q as the magnet leaves the coil?

Oct/Nov 2024

Which device operates because of electromagnetic induction?

Oct/Nov 2025