Question

The internal resistance of a primary cell is 4 ohm. It generates a current of 0.2 amp in an external resistance of 21 ohm. The rate at which chemical energy is consumed in providing the current is

• A. $0.42J/s$
• B. $0.84J/s$
• C. $5J/s$
• D. $1J/s$

Answer 1

Answer: (D)

$1J/s$

Answer 2

$\frac{H}{t} = i^{2}R$. Here total $R = (21 + 4) = 25\Omega$

⇒ Rate of energy consumed $= 0.2 \times 0.2 \times 25 = 1J/s$