Question

Calculate the quanta of radiations of frequency $4.67\times {10}^{13}{s}^{-1}$ that must be absorbed in order to melt 5 g of ice (The energy required to melt 1 g of ice is 333 J)

• A. $3.36\times {10}^{18}$
• B. 17
• C. $5.38\times {10}^{22}$
• D. $3.35\times {10}^{21}$
  

Answer 1

The correct option is C $5.38\times {10}^{22}$

Explanation :
Energy required to melt 5 g of ice,
$=5\times 333=1665J$

$E=h\nu$

$=6.626\times {10}^{-34}\times 4.67\times {10}^{13}$

$=30.91\times {10}^{-21}J$
Quanta required to melt 5 g of ice

$=\frac{1665}{30.91\times {10}^{-21}}$

$=53.8\times {10}^{21}=5.38\times {10}^{22}$