14. A strong magnetic north pole is moved towards 3 substances in turn. Which of these answers describes the result correctly?

15. Which of the following substances readily makes a strong magnet when induced but quickly loses its magnetism?

• A. Copper
• B. Iron
• C. Steel
• D. Carbon

16. Which of the following lists identifies the three key features needed to make a strong electromagnet?

• A. Current, coil and iron core
• B. Charge, coil and copper core
• C. Coil, current and copper core
• D. Current, casing and coil

17. A step up transformer changes the voltage output compared to the input. Which of these statements best describes the voltage output?

• A. An increased d.c. voltage
• B. An increased a.c. voltage
• C. A decreased d.c. voltage
• D. A decreased a.c. voltage

18-21: A transformer is used to increase or decrease the voltage for an appliance.

What are the missing values in this table showing different transformers?

22.A circular magnetic field pattern can be produced by..

• A. a current in a solenoid
• B. a bar magnet
• C. a current in a straight wire
• D. a current in a single loop of wire

23. A wire conductor moving through a magnetic field can produce an E.M.F.in the conductor. What is this effect called?

• A. potential difference
• B. motor effect
• C. generator effect
• D. induction

24+25: A magnet is dropped through a coil connected to a voltmeter as shown. The voltmeter needle initially moves to the right showing a positve reading.

24. Which of these will make the voltmeter reading smaller but still positive?

• A). drop the south pole through first
• B). have more coils on the magnet
• C). move the magnet slowly through the coil
• D). use a stronger magnet

25. Which of these will make the voltmeter initially move to the left?

• A). drop the south pole through first
• B). have more coils on the magnet
• C). move the magnet slowly through the coil
• D). use a stronger magnet