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Magnetism and electromagnetism

Magnetism and electromagnetism

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Question 17

An electric fence system is used on farms to contain livestock. The system consists of:

  • a transformer unit connected to a 240 V a.c. mains supply
  • a metal wire carrying a high voltage
  • plastic insulators that support the fence wire on wooden posts
  • a wireless transmitter that sends radio waves to a receiver in the farmhouse to monitor the status of the fence.
a.

Radio waves are electromagnetic waves. State two properties that are common to all electromagnetic waves.

[2]
b.

Which of these electromagnetic radiations has a frequency greater than visible light?

  • A infrared
  • B radio waves
  • C microwaves
  • D X-rays
[1]
c.

The transformer supplies an output voltage of 6000 V a.c. to the fence wire. The input voltage to the transformer is 240 V a.c.

Give the name of this type of transformer.

[1]
d.

State the relationship between input (primary) voltage, output (secondary) voltage, primary turns, and secondary turns.

[1]
e.

There are 150 turns150\text{ turns}150 turns on the primary coil. Calculate the number of turns on the secondary coil.

[3]
f.

Suggest a reason why the wire is supported by plastic insulators on the wooden posts.

[2]
Markscheme

Magnetism and electromagnetism Questions

  1. IGCSE
  2. /Physics
  3. /Magnetism and electromagnetism

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