A filament lamp is rated at its operating temperature of

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

A filament lamp is rated

12\,\text{V},\;0.50\,\text{A}

at its operating temperature of

1000\,^{\circ}\text{C}

. The filament’s temperature coefficient is approximately

4.5\times10^{-3}\,^{\circ}\text{C}^{-1}

(assumed constant). When the lamp is first switched on in a room at

20\,^{\circ}\text{C}

and connected to

12\,\text{V}

, the current drawn is closest to (a)

0.50\,\text{A}

(b)

2.2\,\text{A}

(c)

2.7\,\text{A}

(d)

1.6\,\text{A}