An electric bulb of 500 watt at 100 volt is used in a circuit having a 200 V supply. Calculate the resistance R to be connected in series with the bulb so that the power delivered by the bulb is 500 W.

In the given figure, the emf of the cell is 2.2 V and if internal resistance is 0.6$$\Omega$$. Calculate the power dissipated in the whole circuit :

What equal length of an iron wire and a copper-nickel alloy wire, each of 2 mm diameter connected parallel to give an equivalent resistance of 3$$\Omega$$ ?

(Given resistivities of iron and copper-nickel alloy wire are 12 $$\mu$$$$\Omega$$ and 51 $$\mu$$$$\Omega$$ cm respectively)

The resistance of a conductor at 15$$^\circ$$C is 16$$\Omega$$ and at 100$$^\circ$$C is 20$$\Omega$$. What will be the temperature coefficient of resistance of the conductor?