Current Electricity - Result Question 69
74. A current of $3 amp$ flows through the $2 \Omega$ resistor shown in the circuit. The power dissipated in the $5-\Omega$ resistor is:
(a) 4 watt
(b) 2 watt
(c) 1 watt
(d) 5 watt
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Answer:
Correct Answer: 74. (d)
Solution:
- (d) Clearly, $2 \Omega, 4 \Omega$ and ( $1+5) \Omega$ resistors are in parallel. Hence, potential difference is same across each of them.
$\therefore I_1 \times 2=I_2 \times 4=I_3 \times 6$
Given $I_1=3 A \quad \therefore I_1 \times 2=I_3 \times 6$
Given $I_1=3 A$.
$\therefore I_1 \times 2=I_3 \times 6$ provides
$I_3=\frac{I_1 \times 2}{6}=\frac{3 \times 2}{6}=1 A$.
Now, the potential across the $5 \Omega$ resistor is
$V=I_3 \times 5=1 \times 5=5 V$.
$\therefore$ the power dissipated in the $5 \Omega$ resistor
$P=\frac{V^{2}}{R}=\frac{5^{2}}{5}=5$ watt.
