## Monday, October 12, 2009

### IIT JEE Physics Final Revision Set 30

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A cylinder of mass 1 kg is given heat of 20000J at atmospheric pressure. If initially temperature of cylinder is 20°C.

1.Find final temperature of the cylinder.
2. Find the work done by the cylinder.
3 Find the change in internal energy of the cylinder.
(Given that Specific heat of cylinder= 400 J kg-1 0C-1, Coefficient of volume expansion
= 9 × 10-5 °C-1, Atmospheric pressure = 105 N/m2 and Density of cylinder = 9000 kg/m³)

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In a moving coil galvanometer, torque on the coil can be expressed as τ = ki, where i is current through the wire and k is constant. The rectangular coil of the galvanometer having numbers of turns N, area A and moment of inertia I is placed in magnetic field B.

4. Find k in terms of given parameters N, I, A and B.
5. Find the torsional constant of the spring, if a current i0 produces a deflection of π/2 in the coil.
6. the maximum angle through which coil is deflected, if charge Q is passed through the coil almost instantaneously. (Ignore the damping in mechanical oscillations)

Source 2005 JEE Mains