A constant voltage is applied between the two ends of a metallic wire. If both the length and the radius of the wire are doubled, the rate of heat developed in the wire
Will be doubled
Will be halved
Will remain the same
Will be quadrupled
Resistances ${R_1}$ and ${R_2}$ are joined in parallel and a current is passed so that the amount of heat liberated is ${H_1}$ and ${H_2}$ respectively. The ratio $\frac{{{H_1}}}{{{H_2}}}$ has the value
A piece of fuse wire melts when a current of $15\, ampere$ flows through it. With this current, if it dissipates $22.5\, W$, the resistance of fuse wire will be .............. $\Omega$
$A\,\,{5\,^o}C$ rise in the temperature is observed in a conductor by passing some current. When the current is doubled, then rise in temperature will be equal to ............. $^oC$
An electric bulb rated for $500\, watts$ at $100\, volts$ is used in a circuit having a $200-volt$ supply. The resistance $R$ that must be put in series with the bulb, so that the bulb draws $500\, W$ is .................. $\Omega$
The two bulbs as in the above question are connected in series to a $200\, volt$ line. Then