An electric lamp has a filament whose resistance at its operating temperature is .

MATHEMATICS · Multi-part · ISC · Physics · Current Electricity · Ohm's law, V-I graphs and ohmic/non-ohmic conductors

Problem

An electric lamp has a filament whose resistance at its operating temperature is

920\,\Omega

. (i) The lamp is connected to a

230\,\text{V}

mains supply. Calculate the power consumed by the lamp at its rated voltage. (ii) The same lamp is accidentally connected to a

115\,\text{V}

supply. Calculate the power now consumed and state, with reason, whether the lamp will glow with normal brightness.