Question:
The height of victoria falls is $63 \mathrm{~m}$. What is the difference in temperature of water at the top and at the bottom of fall?
[Given $1 \mathrm{cal}=4.2 \mathrm{~J}$ and specific heat of water $\left.=1 \mathrm{cal} \mathrm{g}^{-1} \mathrm{C}^{-1}\right]$
Correct Option: 1
Solution:
Change in P.E. = Heat energy
$\mathrm{mgh}=\mathrm{mS} \Delta \mathrm{T}$
$\Delta \mathrm{T}=\frac{\mathrm{gh}}{\mathrm{S}}$
$=\frac{10 \times 63}{4200 \mathrm{~J} / \mathrm{kgC}}$
$=0.147^{\circ} \mathrm{C}$