Current Electricity Question 20
Question 20 - 2024 (30 Jan Shift 2)
When a potential difference $\mathrm{V}$ is applied across a wire of resistance $\mathrm{R}$, it dissipates energy at a rate $\mathrm{W}$. If the wire is cut into two halves and these halves are connected mutually parallel across the same supply, the same supply, the energy dissipation rate will become:
(1) $1 / 4 \mathrm{~W}$
(2) $1 / 2 \mathrm{~W}$
(3) $2 \mathrm{~W}$
(4) $4 \mathrm{~W}$
Show Answer
Answer: (4)
Solution:
$\frac{\mathrm{v}^{2}}{\mathrm{R}}=\mathrm{W}$…(i)
$\frac{\mathrm{v}^{2}}{\frac{1}{2}\left(\frac{\mathrm{R}}{2}\right)}=\mathrm{W}^{\prime}$
From (i) $\backslash &$ (ii),
we get $\mathrm{W}^{\prime}=4 \mathrm{~W}$
