Chapter 6 class 12 Physics
Q.1 The magnetic flux through a coil perpendicular to the plane is bearing accordingly to the relation phi = 5t^3 + 4t² + 2t - 5 wb. Calculate the induced current through the coil at t= 2 s if the resistance of the coil is 5 ohm. Ans. 15.6 A
Q.2 A coil of area 0.04 m² having 1000 turns is suspended perpendicular to a magnetic field of 5.0 x 10^-5 Weber per metre square. It is rotated through 90° in 0.2 s. Calculate the average EMF induced in it. Ans. 0.01V
Q.3 A conducting circular loop is placed in a uniform magnetic field such that its plane is perpendicular to the field having a strength 0.5 tesla. If the radius of the coil decreases steadily at the rate of 10^-2 m/s. What will be the magnitude of induced EMF when radius of the coil is 7 cm. Ans. 2.2 x 10^-3 V
Q.4 The magnetic field in the cylindrical region shown in the figure increases at a constant rate of 20 m Tesla per second. Each side of the square loop ABCD has a length of 1 cm and resistance of four ohm. Find the current in the wire AB if they switch S is closed. Ans 1.25 x 10^-7 A anti-clockwise
Q.5 A circular coil is rotated in a uniform magnetic field 4×10^ -2 T about a diameter. Area of a coil is 25 cm² and angular velocity is 300 revolutions per minute. The resistance of the coil is 2 ohm. Find the average induced EMF, induced current and charge in a) half rotation and b) full rotation. Ans. A) 2 x 10^-3 V, 10^-3 A , q = 10^-4 C B) 0,0,0
Inductance
Q.6 What is the self inductance of a coil, in which magnetic flux of 40 MilliWebber is produced when current of 2A flows through it? Ans. 2 x10-² Henry.
Q.7 A coil has inductance of 4mH. If the current through the coil changes from 0.25 A to 2 A during 0.5 seconds, find the average voltage dropped across the inductor. Ans. 14 mV
Q.8 A coil has a self inductance of 10 mH. What is the maximum magnitude of the induced EMF in the inductor, when a current I=0.1 sin200t A is sent through it. Ans. 0.2V
Q.9 The current in a solenoid of 200 turns, having a length of 20 cm and a radius of 1/2π cm, changes at a rate of 0.2 A/s. Find the EMF induced in it. Ans. 4 x10^-7 V
Q.10 If L =3/4 H and current is decreasing at rate of 0.04 impair per second find magnitude of self induced EMF. Ans. 0.03V
Q.11 If R= 2 ohm, E = 24 V, L= 4H, I= 10 A are decreasing at rate of 0.5 A/s. Find the potential difference between VN -VM. Ans6V
Q.12 If an emf of 0.5 V is developed in the secondary coil, when current in primary coil changes from 5.0 A to 2.0 A in 300 Milliseconds. Calculate the mutual inductance of the two coils. Ans. 0.05H
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