Figure shows three similar lamps $L_1, L_2$ and $L_3$ connected across a power supply. If the lamp $L_3$ fuses, how will the light emitted by $L_1$ and $L_2$ change ?
No change
Brilliance of $L_1$ decreases and that of $L_2$ increases
Brilliance of both $L_1$ and $L_2$ increases
Brilliance of both $L_1$ and $L_2$ decreases
A bulb rated at ($100\,W$ - $200\,V$) is used on a $100\,V$ line. The current in the bulb is
The voltage of clouds is $4 \times 10^6\,volt$ with respect to round. In a lighteing strike lasting $100\,m\,sec$, a charge of $4\,coulombs$ is delivered to the ground. The power of lightening strike is
Incandescent bulbs are designed by keeping in mind that the resistance of their filament increases with the increase in temperature. If at room temperature, $100 \mathrm{~W}, 60 \mathrm{~W}$ and $40 \mathrm{~W}$ bulbs have filament resistances $\mathrm{R}_{100}, \mathrm{R}_{60}$ and $\mathrm{R}_{40}$, respectively, the relation between these resistances is
A resistor dissipates $192\, {J}$ of energy in $1\, {s}$ when a current of $4\, {A}$ is passed through it. Now, when the current is doubled, the amount of thermal energy dissipated in $5 \,{s}$ in $.....\,J.$
Forty electric bulbs are connected in series across a $220\, V$ supply. After one bulb is fused, the remaining $39$ are connected again in series across the same supply. The illumination will be