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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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A (current vs time) graph of the current passing through a solenoid is shown in Fig . For which time is the back electromotive force (u) a maximum. If the back emf at t = 3s is e, find the back emf at t = 7 s, 15s and 40s. OA, AB and BC are straight line segments.

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

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There are two coils A and B seperated by some distance. If a current of 2 A flows through A, a magnetic flux of 10-2 Wb passes through B (no current through B). If no current passes through A and a current of 1 A passes through B, what is the flux through

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

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A magnetic field ` hatB = B_o sin( ωt) hat k` covers a large region where a wire AB slides smoothly over two parallel conductors separated by a distance d (Fig.). The wires are in the x-y plane. The wire AB (of length d) has resistance R and the parallel wires have negligible resistance. If AB is moving with velocity v, what is the current in the circuit. What is the force needed to keep the wire moving at constant

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

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A conducting wire XY of mass m and neglibile resistance slides smoothly on two parallel conducting wires as shown in Fig . The closed circuit has a resistance R due to AC. AB and CD are perfect conductors. There is a magnetic field` B = B(t )hatk` . Write

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

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A conducting wire XY of mass m and neglibile resistance slides smoothly on two parallel conducting wires as shown in Fig . The closed circuit has a resistance R due to AC. AB and CD are perfect conductors. There is a magnetic field` B = B(t )hatk` . If

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

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A conducting wire XY of mass m and neglibile resistance slides smoothly on two parallel conducting wires as shown in Fig . The closed circuit has a resistance R due to AC. AB and CD are perfect conductors. There is a magnetic field` B = B(t )hatk` . For

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

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ODBAC is a fixed rectangular conductor of negilible resistance (CO is not connnected) and OP is a conductor which rotates clockwise with an angular velocity ω (Fig ). The entire system is in a uniform magnetic field B whose direction is along the normal to the surface of the rectangular conductor ABDC. The conductor OP is in electric contact with ABDC. The rotating conductor has a resistance of λ per unit length. Find the current in the rotating conductor, as it rotates by

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

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Consider an infinitely long wire carrying a current I (t ), with` dI/ dt = λ = constant`. Find the current produced in the rectangular loop of wire ABCD if its resistance is R (Fig.

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

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A rectangular loop of wire ABCD is kept close to an infinitely long wire carrying a current` I (t ) = I_o (1 – t /T ) `for 0 ≤ t ≤ T and `I (0) = 0 'for' t > T` (Fig. ). Find the total charge passing through a given point in the loop, in time T. The resistance of the loop is R.

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

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A magnetic field B is confined to a region r ≤ a and points out of the paper (the z-axis), r = 0 being the centre of the circular region. A charged ring (charge = Q) of radius b, b > a and mass m lies in the x-y plane with its centre at the origin. The ring is free to rotate and is at rest. The magnetic field is brought to zero in time Δt. Find the angular velocity ω of the ring after the field

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

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A rod of mass m and resistance R slides smoothly over two parallel perfectly conducting wires kept sloping at an angle θ with respect to the horizontal (Fig. ). The circuit is closed through a perfect conductor at the top. There is a constant magnetic field B along the vertical direction. If the rod is initially at rest, find the velocity of the rod as a function of

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

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Find the current in the sliding rod AB (resistance = R) for the arrangement shown in Fig . B is constant and is out of the paper. Parallel wires have no resistance. v is constant. Switch S is closed at time t =

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

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Find the current in the sliding rod AB (resistance = R) for the arrangement shown in Fig . B is constant and is out of the paper. Parallel wires have no resistance. v is constant. Switch S is closed at time t = 0.

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

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A metallic ring of mass m and radius l (ring being horizontal) is falling under gravity in a region having a magnetic field. If z is the vertical direction, the z-component of magnetic field is `B_z = B_o (1+λ z)`. If R is the resistance of the ring and if the ring falls with a velocity v, find the energy lost in the resistance. If the ring has reached a constant velocity, use the conservation of energy to determine v in terms of m, B, λ and acceleration due to gravity

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

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A long solenoid ‘S’ has ‘n’ turns per meter, with diameter ‘a’. At the centre of this coil we place a smaller coil of ‘N’ turns and diameter ‘b’ (where b < a). If the current in the solenoid increases linearly, with time, what is the induced emf appearing in the smaller coil. Plot graph showing nature of variation in emf, if current varies as a function of mt2 +

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

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