Two heaters designed for the same voltage have different power ratings

PHYSICS · Multi correct · CBSE · Physics · Electricity · Electricity

Problem

Two heaters designed for the same voltage

V

have different power ratings. When connected individually across a source of voltage

V

, they each produce an amount of heat

H

in times

t_1

and

t_2

, respectively. When used together across the same source, they produce

H

in time

t

. (a) If they are in series,

t=t_1+t_2

. (b) If they are in series,

t=2(t_1+t_2)

. (c) If they are in parallel,

t=\frac{t_1t_2}{t_1+t_2}

. (d) If they are in parallel,

t=\frac{t_1t_2}{2(t_1+t_2)}