Question

The work function for aluminium surface is 4.2 eV and that for sodium surface is 2.0 eV. The two metals were illuminated with appropriate radiations so as to cause photoemission. Then choose the correct statement.

• A. Both aluminium and sodium will have the same threshold frequency.
  
• B. The threshold frequency of aluminium will be more than that of sodium.
  
• C. The threshold frequency of aluminum will be less than that of sodium.
  
• D. Cannot say

Answer 1

The correct option is B The threshold frequency of aluminium will be more than that of sodium.


We know that, work function, $W_0=h{\nu }_0$
Thus, the greater the work function, the higher is the threshold frequency and the correct choice is (b).