Recent questions in 12th Physics

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A positive charge Q is uniformly distributed along a circular ring of radius R. A small test charge q is placed at the centre of the ring as shown in then

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A square of side L meters lies in the x-y plane in a region, where the magnetic field is given by `B =B_o (2hati + 3hatj + 4hatk)` where Bo is constant. The magnitude of flux passing through the square

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A loop, made of straight edges has six corners at A(0,0,0), B(L,O,0) C(L,L,0), D(0,L,0) E(0,L,L) and F(0,0,L). A magnetic field ` B=B_o( hati +hat k)T` is present in the region. The flux passing through the loop ABCDEFA (in that order)

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A cylindrical bar magnet is rotated about its axis (Fig ). A wire is connected from the axis and is made to touch the cylindrical surface through a contact.

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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There are two coils A and B as shown in Fig A current starts flowing in B as shown, when A is moved towards B and stops when A stops moving. The current in A is counterclockwise. B is kept stationary when A moves. We can infer

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Same as problem 4 except the coil A is made to rotate about a vertical axis (Fig ). No current flows in B if A is at rest. The current in coil A, when the current in B (at t = 0) is counterclockwise and the coil A is as shown at this instant, t = 0,

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The self inductance L of a solenoid of length l and area of crosssection A, with a fixed number of turns N increases

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A metal plate is getting heated. It can be

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An e.m.f is produced in a coil, which is not connected to an external voltage source. This can be due

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The mutual inductance M12 of coil 1 with respect to coil

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A circular coil expands radially in a region of magnetic field and no electromotive force is produced in the coil. This can be

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Consider a magnet surrounded by a wire with an on/off switch S (Fig ). If the switch is thrown from the off position (open circuit) to the on position (closed circuit), will a current flow in the circuit? Explain. Bar magnet N Circuit closed Bar magnet N Circuit open Fig.

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A wire in the form of a tightly wound solenoid is connected to a DC source, and carries a current. If the coil is stretched so that there are gaps between successive elements of the spiral coil, will the current increase or decrease?

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, will the current increase or decrease?

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Consider a metal ring kept on top of a fixed solenoid (say on a carboard) (Fig ). The centre of the ring coincides with the axis of the solenoid. If the current is suddenly switched on, the metal ring jumps up.

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Consider a metal ring kept (supported by a cardboard) on top of a fixed solenoid carrying a current I (see Fig ). The centre of the ring coincides with the axis of the solenoid. If the current in the solenoid is switched off, what will happen to the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Consider a metallic pipe with an inner radius of 1 cm. If a cylindrical bar magnet of radius 0.8cm is dropped through the pipe, it takes more time to come down than it takes for a similar unmagnetised cylindrical iron bar dropped through the metallic pipe.

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A magnetic field in a certain region is given by ` B = B_o cos (ωt)hat k` and a coil of radius a with resistance R is placed in the x-y plane with its centre at the origin in the magnetic field (see Fig ) . Find the magnitude and the direction of the current at (a, 0, 0) at t = π/2ω, t = π/ω and t =

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Consider a closed loop C in a magnetic field (Fig ). The flux passing through the loop is defined by choosing a surface whose edge coincides with the loop and using the formula φ = B1.dA1 + B2.dA2 + ... . Now if we chose two different surfaces S1 and S2 having C as their edge, would we get the same answer for flux. Jusity your

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Find the current in the wire for the configuration shown in Fig . Wire PQ has negligible resistance. B, the magnetic field is coming out of the paper. θ is a fixed angle made by PQ travelling smoothly over two conducting parallel wires seperated by a distance

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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