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A long solenoid of radius carries a time (t)-dependent current . A ring of radius is placed coaxially near its middle. During the time interval , the induced current and the induced in the ring change as:
A conducting circular loop made of a thin wire, has area and resistance . It is placed perpendicular to a time dependent magnetic field . The field is uniform in space. Then the net charge flowing through the loop during and is close to:
The figure shows a square loop of side which is connected to a network of resistances. The whole setup is moving towards right with a constant speed of . At some instant, a part of L is in a uniform magnetic field of , perpendicular to the plane of the loop. If the resistance of is , the current in the loop at that instant will be close to :
A power transmission line feeds input power at to a step down transformer with its primary windings having turns, giving the output power at . If the current in the primary of the transformer is , and its efficiency is , the output current would be:
A coil of cross-sectional area having turns is placed in a uniform magnetic field . When it is rotated with an angular velocity , the maximum e.m.f. induced in the coil will be
A small circle loop of wire of radius a is located at the centre of a much larger circular wire loop of radius . The two loops are in the same plane. The outer loop of radius carries an alternating current . The emf induced in the smaller inner loop is nearly :
Consider a thin metallic sheet perpendicular to the plane of the paper moving with speed in a uniform magnetic field B going into the plane of the paper (See figure). If charge densities and are induced on the left and right surfaces, respectively, of the sheet then (ignore fringe effects) :
A fighter plane of length 20 m, wing span (distance from tip of one wing to the tip of the other wing) of 15 m and height 5 m is flying towards east over Delhi. Its speed is . The earth's magnetic field over Delhi is T with the declination angle and dip of such that . If the voltage developed is between the lower and upper side of the plane and between the tips of the wings then and are close to
A conducting metal circular-wire-loop of radius r is placed perpendicular to a magnetic field which varies with time as , where and are constants, at time t = 0. If the resistance of the loop is R then the heat generated in the loop after a long time is