KEELEKTROMAGNETAN

Diagram shows a transformer used to light up a bulb of 6 V, 12 W at normal brightness. If the number of turns on the primary coils is 1000 turns, what is the number of turns on the secondary coil ?

• 5

• 17

• 25

• 50

Diagram shows an electric motor. Which graph shows the output voltage against time when the coil rotates?

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All the following are causes of energy loss in transformers except

• Hysteresis

• Eddy currents

• Types of transformer

• Leakage of magnetic flux

Diagram shows a left hand which represents the Fleming’s Left-Hand Rule. What does X represents of ?

• Force

• Magnetic field

• Electrical current

• Resistance

Diagram 23 shows a copper rod cut magnetic flux. Which of the following pair is correct to show the direction of induced current and direction of deflection of pointer in galvanometer?

• P, left

• Q, right

• P, right

• Q, left

Diagram shows a bar magnet moved towards a solenoid. Which of this action will increase the deflection of galvanometer pointer?

• reduce the number of turns of the solenoid

• increase the diameter of the solenoid

• increase the speed of the bar magnet

• change the polarity of the bar magnet

Diagram shows a current carrying conductor in a magnetic field. What will happen to the coil?

• Static

• Rotates clockwise

• Rotates anti clockwise

• Rotates in alternate directions

The function of a transformer in an electrical energy transmission system is to

• increase the power

• decrease resistance

• change the potential difference

• speed up the time of transmission

What is the function of the laminated iron core in a transformer?

• reduce the resistance of the coil

• reduce eddy current

• reduce the leakage of magnetic flux

• reduce the rate of change of the magnetic field

Diagram shows a current carrying conductor is placed in a magnetic field. Which of the following A, B, C and D shows the direction of force acting on the conductor?

• A

• B

• C

• D