Who will spend more eletrical energy,500 W TV set in 30 mins or 600W heater in 20 mins?

An electric heater of 1200 W is operated for 3 hrs daily. What will be the electrical consumption expenses for that in the month of June ? (The electric company charges Rs 5 per unit of energy.)

Which will require more energy, heating a 2.0 kg block of lead by 30 K or heating a 4.0 kg block of copper by 5 K? (S_lead=128 J kg^-1 K^-1 , S_copper = 387 J kg^-1 K^-1 )

Which will require more energy, heating a 2.0 kg block of lead by 30 K or heating a 4.0 kg block of copper by 5 K? ( s_("lead ") = 128 J kg^(-1) K^(-1), s_("copper") = 387 J kg^(-1) K^(-1) )

Solve the following examples/ numerical problems. A electric iron rated 750 w is operated for 2 hours/ day. How much energy is consumed by the electric iron for 30 days ?

A thermally insulated rigid container contains an ideal gas heated by a filament of resistance 100 Omega through a current of 1 A for 5 min then change in internal energy

The collector supply voltage is 6 V and the voltage drop across a resistor of 600 Omega in the collector circuit is 0.6 V in a transistor connected in common emitter mode. If the current gain is 20, the base current is

A liquid of mass 250 is kept warm in a vessel using an electric heater. The liquid is maintained at 57^@C when the power supplied by the heater is 30 W and surrounding temperature is 27^@C . As the heater is switched off, it took 10 s time for the temperature of the liquid to fall from 47^@C to 46.9^@C . The specific heal capacity of the liquid is

A river is flowing from W to E with a speed of 5 m/min. A man can swim in still water with a velocity 10 m/min. In which direction should the man swim so as to take the shortest possible path to go to the south?

Two resistors of resistance 20 Omega and 30 Omega are connected in series and potential difference of 5V is applied across the combination. Find the potential difference across each resistor.