The number of electrons moving per second through the filament of a lamp of $60 \text{ W}$ operating at $120 \text{ V}$ is nearly $(e = 1.6 \times 10^{-19} \text{ C})$

Assertion : When current through a bulb decreases by $0.5\%$,the glow of bulb decreases by $1\%$.
Reason : Glow (Power) is directly proportional to the square of current.

$A$ Watt-hour meter measures:

If ${R_1}$ and ${R_2}$ are respectively the filament resistances of a $200 \ W$ bulb and $100 \ W$ bulb designed to operate on the same voltage,then

An expression for the rate of heat generated,if a current of $I$ ampere flows through a resistance of $R$ $\Omega$,is

Four wires of the same diameter are connected in turn between two points,maintained at a constant potential difference. Their resistivities and lengths are: $\rho$ and $L$ (wire $1$),$1.2\rho$ and $1.2L$ (wire $2$),$0.9\rho$ and $0.9L$ (wire $3$),and $\rho$ and $1.5L$ (wire $4$). Rank the wires according to the rates at which energy is dissipated as heat,greatest first.