When a current-carrying conductor is placed in a magnetic field, the conductor will experience a _______

• pressure

• heat

• force

• impulse

Which is the correct rule to determine the direction of the force or motion of the conductor carrying current in a magnetic field?

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Catapult field is the resultant magnetic field produced by

• interaction between the electric field from a current-carrying conductor and the magnetic field from permanent magnet

• interaction between the magnetic field from a current-carrying conductor and the magnetic field from permanent magnet

• superimposed between the magnetic field and electric field of the current-carrying conductor

• interaction between two magnetic fields from current-carrying conductor

Figure above shows the results of increasing the current which produces a bigger swing. Which are the best methods to increase the magnitude of the current? (More than 1 answer)

• Using shorter wire

• Using thinner wire

• Increase the e.m.f

• Increase the number of turns of wire

Figure above shows the arrangement of apparatus to study the effect of a force on a current-carrying conductor.

State the direction of the current along the copper wire and its motion?

• Current flow: From X to Y

  Motion of Copper wire: To the left

• Current flow: From X to Y

  Motion of Copper wire: To the right

• Current flow: From Y to X

  Motion of Copper wire: To the left

• Current flow: From Y to X

  Motion of Copper wire: To the right

The coil carrying current in a magnetic field rotates due to __________ with equal magnitudes but __________ on the both sides of the coil which produces a __________.

• single force; same direction; momentum

• two pair of forces; opposite direction; momentum

• single force; same direction; turning effect

• two pair of forces; opposite direction; turning effect

Which diagram shows the correct magnetic field pattern of the current-carrying coil?

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What is the functions of commutator?

• Reverse the direction of current in the coil every half rotation so that the coil continues to turn in same direction

• To contact with the commutator so the current from the battery enters the coil.

• Push the brush so it will always contact with the commutator.

Diagram shows a coil placed between the poles of a permanent magnet and is connected to the external circuit.Determine the direction of rotation of the coil when the switch is closed.

• Clock wise

• Anti Clock wise

• Alternately, anticlockwise then clockwise

• Alternately, clockwise then anticlockwise

Which factor does not influence the speed of rotation of a direct current motor?

• Current in the coil

• Strength of magnetic field

• Coil with more turns

• Use soft iron core