(i) An electric iron consumes energy at the rate of 420W when heating is at the maximum rate and 180W when heating is at the minimum rate. The applied voltage is 220 V. what is the current in each case?
(ii) What is co-efficient of real expansion?

An electric iron consumes energy at the rate of 420 W when heating is at the maximum rate and 180 W when heating is at the minimum rate. The applied voltage is 220V. What is the current in each case.

When a metallic bar is heated from 0^@ C to 100^@C , its length increases by 0.05 %, what is the co-efficient of linear expansion of the metal?

An iron ring measuring 15.00 cm in diameter is a be shrunk on a pulley which is 15.05 cm in diameter. All measurements refer to the room temperature 20^0 C . To What minimum temperature should the ring be heated to make the job possible? Calculate the strain developed in the ring when in comes to the room temperature. Coefficient of linear expansion of iron =12 xx 10^(-6) C^(-1) .

Heat at the rate of 200 W is produced in an X-ray tube operating at 20 kV. Find the current in the circuit. Assume that only a small fraction of the kinetic energy of electron is converted into X-rays.

What is the resistance of heating element of the heater when 20 A current passing through it at a potential of 220 V ?

The coil of an electric bulb takes 40 watts to start glowing. If more than 40 W is supplied, 60% of the extra power is converted into light and the remaining into heat. The bulb consumes 100 W at 220 V. Find the percentage drop in the light intensity at a point if the supply voltage changes from 220 V to 200 V .

A conducting wire ab of length l, resistance r and mass m starts sliding at t = 0 down a smooth, vertical, thick pair of connected rails as shown in . A uniform magnetic field B exists in the space in a diraction perpendicular to the plane of the rails. (a) Write the induced emf in the loop at an instant t when the speed of the wire is v. (b) what would be the magnitude and direction of the induced current in the wire? (c) Find the downward acceleration of the wire at this instant. (d) After sufficient time, the wire starts moving with a constant velocity. Find this velocity v_m. (e) Find the velocity of the wire as a function of time. (f) Find the displacement of the wire as a functong of time. (g) Show that the rate of heat developed inte wire is equal to the rate at which the gravitational potential energy is decreased after steady state is reached.

An electric heater supplies heat to a system at a rate or 100 W. If the system performs work at a rate of 75 joules per second at what rate is the internal energy increasing ?

An electric heater supplies heat to a system at a rate of 100W. If system performs work at a rate of 75 joules per second. At what rate is the internal energy increasing?