A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The cross-sectional area of the coil is equal to S = 3.0 mm^2 , the number of turns is N = 60 . When the coil turns through 180^@ about its diameter, a galvanometer connected to the coil indicates a charge q = 4.5muC flowing through it. Find the magnetic induction magnitude between the poles, provided the total resistance of the electric circuit equals R = 40 Omega .

The motion of copper plate is damped when it is allowed to oscillate between the two poles of a magnet. What is the cause of this damping?

In an electric bell, when the metal strip gets attached to the electromagnet , it no longer touches the interrupter , and hence the circuit breaks.

Statement I: A circular metal hop is suspended on the edge by a hook. the hoop can oscillate side to side in the plane of the hoop, or it can oscillate back and forth in a direction perpendicular to the plane of the hoop. The time period of oscillation would be more when oscillation are carried out in the plane of hoop. Statement II: Time period of physical pendulum is more if moment of inertial of the rigid body about corresponding axis passing through the pivoted point is more.

Answer the following: (a) When a parallel plate capacitor is connected across a dc battery, explain briefly how the capacitor gets charged. (b) A parallel plate capacitor of capacitance 'C' is charged to 'V' volt by a battery. After some time the battery is disconnected and the distance between the plates is doubled. Now a slab of dielectric constant 1ltklt2 is introduced to fill the space between the plates. How will the following be affected ? (i) The electric field between the plates of the capacitor. (ii) The energy stored in the capacitor. Justify your answer in each case. (c) The electric potential as a function of distance 'x' is shown in the figure. Draw a graph of the electric field E as a function of x.

In an oscillating LC circuit the maximum charge on the capacitor is Q. The charges on the capacitor when the energy is stored equally between the electric and magnetic field is

In an oscillating LC circuit the maximum charge on the capacitor is Q. The charges on the capacitor when the energy is stored equally between the electric and magnetic field is

An inductor of inductance 2.0 mH s connected across a charged capacitor of capacitance 5.0 mu F and the resulting LC circuit is set oscillating at its natural frequency. Let Q denote the instantaneous charge on the capacitor and I the current in the circuit. It is found that the maximum value of charge Q is 200 mu C . a. When Q = 100 mu C , what is the value of |(dI)/(dt)| ? b. When Q = 200 mu C , what is the value of I ? c. Find the maximum value of I . d. When I is equal to one-half its maximum value, what is the value of |Q| ?

A pendulum has a period T for small oscillations. An obstacle is placed directly beneath the pivot, so that only the lowest one - quarter of the string can follow the pendulum bob when it swings to the left of its resting position. The pendulum is released from rest at a certain point. How long will it take to return to that point again ? In answering this question, you may assume that the angle between the moving string and the vertical stays small throughout the motion.

A wire PQ of mass 10g is at rest on two parallel metal rails.The separation betweem the rails is 4.9 cm.A magnetic field if 0.80 T is applied perpendicular to the plane of the rails, directed downwads. The resisitance of the circuit is slowly decreased. When the resistance to bleow 10 Omega the wire PQ begins to slide on the rails .Calculate the coefficient of friction between the wire and the rails