The carrier frequency of a transmitter is provided by a tank circuit of a coil of inductance 49 $$\mu $$H and a capacitance of 2.5 nF. It is modulated by an audio signal of $$12$$ $$kHz.$$ The frequency range occupied by the side bands is :

A constant voltages is applied between two ends of a metallic wire. If the length is halved and the radius of the wire is doubled, the rate of heat developed in the wire will be :

A body takes 10 minutes to cool from 60^oC to 50^oC. The tempertature of surroundings is constant at 25^oC. Then, the temperature of the body after next 10 minutes will be approximately :