The energy required to melt 1g. ice is 33J. The number of quanta of radiation of frequency
4.67 × 10¹³ sec^–1 that must be absorbed to melt 10g ice is:

Energy required to melt 1g ice =33J.

Energy required to melt 10g ice =33×10=330J.

Radiation frequency (ν)=4.67×10¹³s−1
 

As we know, the energy of radiation is given by:

E=hν

Here, h= Planck's constant =6.62×10⁻³⁴J.s

∴E=6.62×10 −34×4.67×10¹³
 

⇒E=3.09×10 ^-20J

∴ No. of quanta required $=\frac{330}{3.09 \times {10}^{-20}}=1.067\times {10}^{22}$