B M Sharma Solutions for Chapter: Heating Effects of Current, Exercise 3: DPP

If the length of the filament of a heater is reduced by $10\%$, the power of the heater will,

The resistance of the filament of a lamp increases with the increase in temperature. A lamp rated $100 \mathrm{W}$, $220 \mathrm{V}$ is connected across $220 \mathrm{V}$ power supply. If the voltage drops by $10\%$, then the power of lamp will be:

In the following circuit,$18 \mathrm{\Omega }$ resistor develops $2 \mathrm{J} {\mathrm{s}}^{-1}$ due to current flowing through it. The power developed across $10 \mathrm{\Omega }$ resistance is:

For ensuring dissipation of the same energy in all three resistors $R_1$, $R_2$ and $R_3$ connected as shown in the figure, their values must be related as:
   

The resistance of the filament of an electric bulb changes with temperature. If an electric bulb rated $220 \mathrm{V}$ and $100 \mathrm{W}$ is connected $(220\times 0.8) \mathrm{V}$ sources, then the actual power would be:

An electric bulb rated for $500 \mathrm{W}$ at $100 \mathrm{V}$ is used in a circuit having a $200 \mathrm{V}$ supply. The resistance $R$ that must be put in series with the bulb, so that the bulb draws $500 \mathrm{W}$ is:

The wiring of a house has resistance $6 \mathrm{\Omega }$. A $100 \mathrm{W}$ bulb is glowing. If a geyser of $1000 \mathrm{W}$ is switched on, the change in potential drop across the bulb is nearly:

In the following circuit, $5 \mathrm{\Omega }$ resistor develops $45 \mathrm{J} {\mathrm{s}}^{-1}$ due to current flowing through it. The power developed per second across $12 \mathrm{\Omega }$ resistor is: