$A$ Watt-hour meter measures:

The power dissipated by a uniform wire of resistance $100 \Omega$ when a potential difference of $120 \text{ V}$ is applied across its ends is (in $W$)

The emf of a car battery is $12 \ V$. If the internal resistance of the battery is $0.4 \ \Omega$,then the maximum power drawn from the battery is . . . . . . $W$.

$A$ house is served by a $220 \, V$ supply line in a circuit protected by a $9 \, A$ fuse. What is the maximum number of $60 \, W$ lamps in parallel that can be turned on simultaneously?

An electric heater heats a certain amount of water in $5 \, \text{min}$ when connected to a $220 \, \text{V}$ supply. How many minutes will it take to heat the same amount of water when connected to a $110 \, \text{V}$ supply?

$A$ battery with a $12 \, V$ emf has an initial charge of $80 \, A \cdot h$. If the potential across the terminals stays constant until the battery is completely discharged, then this battery can deliver energy at the rate of $120 \, W$ for a time of: (in $ \, h$)