State which metal from the list is used in a compass needle.
State which metal from the list is used for magnetic screening.
State which metal from the list is used for the core of a transformer.
Describe one application of a transformer.
An a.c. generator supplies an input voltage of 220 V to a transformer. In the space below, sketch a graph of the output voltage against time for the a.c. generator.
The transformer’s primary coil contains 1700 turns and its secondary coil contains 85 turns. Calculate the output voltage of the transformer.
Fig. 11.1 shows a magnet beside one end of a solenoid. The solenoid terminals are attached to a very sensitive ammeter. The magnet is then moved to the right at a constant speed, and an ammeter reading is observed. Explain why there is a current in the ammeter.
Explain how the current in the ammeter acts to oppose the change producing it.
The magnet comes to rest when the S-pole reaches the centre of the solenoid. The ammeter reading is observed when the magnet is moved to the left at a constant speed that is lower than its speed in (c)(i). State two ways in which the ammeter reading is different from the reading seen in (c)(i) as the magnet moves to the left.