How much energy in kilowatt-hour $(kWh)$ is consumed in operating ten $50\,W$ bulbs for $10$ hours per day in a month ($30$ days)?

If the power in the external resistance $R$ is maximum,then which of the following statements are correct?
$(i) R = r$
$(ii)$ Power in $R$ is $\frac{E^2}{4R}$
$(iii)$ Input power is $\frac{E^2}{2R}$
$(iv)$ Efficiency is $50\%$

$A$ uniform heating wire of resistance $36 \, \Omega$ is connected across a potential difference of $240 \, V$. The wire is then cut into half and a potential difference of $240 \, V$ is applied across each half separately. The ratio of power dissipation in the first case to the total power dissipation in the second case would be $1:x$,where $x$ is........... .

Assertion: Long distance power transmission is done at high voltage.
Reason: At high voltage supply,power losses are less.

There are four bulbs of power $100 \,W, 200 \,W, 500 \,W$ and $1000 \,W$. Among these, which filament has the highest resistance? (Assuming the same voltage source)

Which of the following is not a unit of power?