The maximum power rating of a $20 \Omega$ resistor is 2 kW . Then, it cannot be used with 300 V DC source because the

The magnitude of resistance $X$ in the circuit shown below in the figure, when no current flows through the $5 \Omega$ resistor, is

A constant voltage is applied between the two ends of a uniform metallic wire, Some heat is developed in it. The heat developed is halved if

24 cells of emf $$1.5 \mathrm{~V}$$ each having internal resistance of $$1 \mathrm{~ohm}$$ are connected to an external resistance of $$1.5 \mathrm{~ohms}$$. To get maximum current