Phy F5 Chap 3 ELECTROMAGNETISM (II)

Diagram 1 shows a current carrying conductor is placed in a magnetic field. The copper rod is moved towards the left when the circuit is completed. What needs to be done to move the copper rod towards the same direction in a longer/further direction?

• Change the polarity of the magnet and increase the current.

• Maintain the polarity of the magnet and reduce 240 V the current.

• Change the direction of the current and reduce the strength of the magnet.

• Maintain the direction of the current and increase the strength of the magnet.

Diagram 2 shows a transformer used to light up a bulb labeled 6 V. 12 W at normal brightness. What happens to the bulb when the number of turns in the primary coil is increased from 200 turns to 300 turns?

• Dimmer

• Brighter

• Blown up

• Remains unchanged

Diagram 3 shows the pointer of a compass pointing to a definite direction when the thin wire is connected to a direct current. The direction of the pointer can be determined by...

• Fleming's left-hand rule

• Right-hand grip rule

• Faraday's law

• Fleming's right-hand

Diagram 4 shows a laptop and its charger. Which pair is correct about the transformer in the charger?

• Type of transformer: Step-down, Characteristics: N_s < N_P

• Type of transformer: Step-up, Characteristics: N_s < N_P

• Type of transformer: Step-down, Characteristics: V_s < V_P

• Type of transformer: Step-up, Characteristics: V_s < V_P

Diagram 5 shows the situation when a bar magnet moves towards a solenoid. The pointer of the galvanometer deflects to the left. The faster the movement, the greater the deflection of the pointer. What is the Principle applied here?

• Hooke's law

• Fleming's right hand rule

• Faraday's law

• Newton's third law of motion

Diagram 6 shows a simple transformer. A bulb is connected to the secondary coil of the transformer. What is the modification that can made to light up the bulb?

• Increasing the number of turns in the primary coil.

• Increasing the number of turns in the secondary coil.

• Reducing the input voltage.

• Replace the 6 V battery with an A.C. power supply.

Which of the following can be used to determine the direction of magnetic field produced by a current carrying conductor?

• Lenz's law

• Faraday's law

• Fleming's left hand rule

• Right-hand grip rule

When the switch in the circuit is closed, paper clips are attracted to the son iron rod as shown below. The number of paper clips attracted to the son iron rod can be increased by...

• Increasing the current in the circuit

• Increasing the resistance in the rheostat

• Decreasing the of turns in the solenoid

• Replacing the battery with alternating current.

Diagram 8 shows current carrying coil in a magnetic fields. Which diagram shows the pattern of the magnetic field produced?

• 
• 
• 
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Diagram 9 shows a student holding a copper rod in a magnetic field. Which step will increase the deflection of the pointer of the galvanometer?

• Use a stronger magnet

• Increase the distance between the two poles of the magnet

• Move the copper rod horizontally

• Use thinner copper rod