`
`
Question:
A uniform heating wire of resistance $36 \Omega$ is connected across a potential difference of $240 \mathrm{~V}$. The wire is then cut into half and potential difference of $240 \mathrm{~V}$ is applied across each half separately. The ratio of power dissipation in first case to the total power dissipation in the second case would be $1: \mathrm{x}$, where $\mathrm{x}$ is..........
Solution:
First case $\mathrm{P}_{1}=\frac{\mathrm{V}^{2}}{\mathrm{R}}=\frac{(240)^{2}}{36}$
Second case Resistance of each half $=18 \Omega$
$\mathrm{P}_{2}=\frac{(240)^{2}}{18}+\frac{(240)^{2}}{18}=\frac{(240)^{2}}{9}$
$\frac{\mathrm{P}_{1}}{\mathrm{P}_{2}}=\frac{1}{4}$
$x=4.00$
.jpg)