A soft spiral spring hangs freely. The lower end of the spring is immersed in a cup of mercury. The spring and the cup are connected to a source of direct current as shown in Fig.. What will happen to the spring after switch K is closed?

Figure 14.26 (a) shows a spring of force constant k clamped rigidly at one end and a mass m attached to its free end. A force F applied at the free end stretches the spring. Figure 14.26 (b) shows the same spring with both endsfree and attached to a mass m at either end. Each end of the spring in Fig. 14.26(b) is stretched by the same force F If the mass in Fig. (a) and the two masses in Fig. (b) are released, what is the period of oscillation in each case ?

Suupose a helical spring is suspended from the roof and a very small weight is attached to its lower end. What will happen to the spring when the current is passed thorugh it? Give reason to support your answer.

A magnet is suspended vertically from a fixed point by means of a spring, as shown in the figure. One end of the magnet hangs inside a coil of wire. The coil is connected in series with a resistance R. The magnet is displaced vertically a small distance D and the released. shown in the figure variation with time t of the vertical displacement d of the magnet from its equilibrium position. State and explain, by reference to electromagnetic induction, the nature of the oscillations of the magnet. Calculate the angular frequency omega_0 of the oscillations.

Figure 14.26 (a) shows a spring of force constant k clamped rigidly at one end and a mass m attached to its free end. A force F applied at the free end stretches the spring. Figure 14.26 (b) shows the same spring with both endsfree and attached to a mass m at either end. Each end of the spring in Fig. 14.26(b) is stretched by the same force F What is the maximum extension of the spring in the two cases ?

A 1 kg block situated on a rough incline is connected to a spring of spring constant 100N m^-1 as shown in Fig. 6.17. The block is released from rest with the spring in the unstretched position. The block moves 10 cm down the incline before coming to rest. Find the coefficient of friction between the block and the incline. Assume that the spring has a negligible mass and the pulley is frictionless.

Direction. In the follwing questions, a statement of assertion is followed by a statement of reason. While answering a question, you are required to choose the correct are out of the given four responses and mark it as (A). If both assertion and reason are true and reason is the correct explanation of the assertion, (B) if both assertion and reason are true but reason is not correct explanation of the assertion. (C) if asssertion is true, but reason if false, (D) if both assertion and reason are false Assertion : The coils of a spring come close to each ohter, when current is passed thorugh it. REason : It is becuase, the coils o spring carry current in the same direction and hence attract each other.

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 mOmega Assume the field to be uniform. Is there an excess charge built up at the ends of the rods when K is open? What if K is closed? :

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 mOmega . Assume the field to be uniform and the rod is moved with a speed of 12 cm/s. How much power is dissipated as heat in the closed circuit? What is the source of this power? :

A rectangular coil of area 5.0xx10^(-4) m^2 and 60 turns is pivoted about one of its vertical sides. The coil is in a radial horizontal field of 90 G (radial here means the field liners are in the plane of the coil for any rotation). What is the torsional constant of the hair spring connected to the coil if a current of 2.0 mA produces an angular deflection of 18^@ ?