Question

From what height a block of ice must fall into a well so that 1/100th of its mass may be melted $(g=10m/s^2)$

• A. $300m$
• B. $336m$
• C. $660m$
• D. none

Answer 1

The correct option is B $336m$

$\text{Solution}:$

We know that latent heat has been converted to energy.

According to question $\frac{1}{100}$ th of the mass of a block of ice may be melted if it falls into a well from a certain height.

So, Q = mL = mgh

Since it is $\frac{1}{100}$ th part we have,

So, $\frac{mL}{100}=mgh$

$⟹\frac{L}{100}=gh$

$⟹\frac{3.4\times {10}^5}{100}=10\times h$

$\therefore 10h=\frac{3.4\times {10}^5}{{10}^2}$

Or h = $3.4\times {10}^2$ m

So $h=340m\approx 336m$

$\text{Hence B is the correct option}$