A resistor and an unknown resistor are connected in parallel across a V battery

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

Problem

20\,\Omega

resistor

(R_1)

and an unknown resistor

(R_2)

are connected in parallel across a

10\,

V battery. If the power dissipated in

R_2

40\,

W, what are the values of

R_2

and the total current drawn from the battery? (a)

R_2 = 4\,\Omega

I = 2.5\,\text{A}

(b)

R_2 = 160\,\Omega

I = 0.5\,\text{A}

(c)

R_2 = 2.5\,\Omega

I = 4.5\,\text{A}

(d)

R_2 = 2.5\,\Omega

I = 4\,\text{A}