21.3 emi

Question 1

• A copper iron
• B iron copper
• C steel copper
• D steel iron

Question 2

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Question 3

• A open the switch
• B reverse teh battery terminals and exchange the poles of the magnet
• C reverse the battery terminals but without exchangig the poles of the magnet
• D turn the metal rod around (P and Q exchanged)

Question 4

• A Both X and Y move away from the coil.
• B Both X and Y move towards the coil.
• C X comes towards the coil, Y moves away from the coil.
• D Y moves towards the coil, X moves away from the coil.

Question 5

• A P, Q and R
• B P and Q only
• C P only
• D R only

Question 6

• A 100 V
• B 200 V
• C 400 V
• D 800 V

Question 7 Which device uses slip rings?

• A a cathode-ray tube
• B a d.c. motor
• C an a.c. generator
• D a solenoid

Question 8 Which graph shows how the output voltage varies with time for a simple a.c. generator?

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Question 9

• A a reading constantly changing from left to right and right to left
• B a steady reading to the left
• C a steady reading to the right

Question 10 The diagram shows a simple step-down transformer used to decrease a voltage. Which part is the primary coil?

• A
• B
• C
• D