Physics
Electromagnetism
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#9 The force is repulsive if the currents are
A) In the same direction
B) In opposite directions
C) Perpendicular to each other
D) At an angle of 45°
#10 The torque on a current loop in a magnetic field is given by
A) $\tau=NIAB\sin\theta$
B) $\tau=NIAB\cos\theta$
C) $\tau=\frac{NIAB}{\sin\theta}$
D) $\tau=\frac{NIAB}{\cos\theta}$
#11 The moving coil galvanometer is based on the principle of
A) Force on a current-carrying conductor
B) Torque on a current loop
C) Both A and B
D) Neither A nor B
#12 The sensitivity of a moving coil galvanometer can be increased by
A) Increasing the number of turns
B) Increasing the magnetic field
C) Decreasing the restoring couple
D) All of these
#13 The conversion of a galvanometer into an ammeter is done by connecting
A) A low resistance in parallel
B) A high resistance in parallel
C) A low resistance in series
D) A high resistance in series
#14 The conversion of a galvanometer into a voltmeter is done by connecting
A) A low resistance in parallel
B) A high resistance in parallel
C) A low resistance in series
D) A high resistance in series
#15 The Hall effect is used to determine
A) Nature of charge carriers
B) Number density of charge carriers
C) Both A and B
D) Neither A nor B
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