Question

Five elements A,B, C, D and E have work functions 1.2eV, 2.4eV. 3.6eV, 4.8eV adn 6 eV respectively. If light of wavelength 4000 A is allowed to fall on these elements, then photoelectrons are emitted by

• A. A, B and C
• B. A, B, C, D and E
• C. A and B
• D. Only E

Answer 1

The correct option is C A and B

According to the question,

$E=\frac{12375}{4000}=3.09eV$

photoelectrons emit if the energy of incident light > work function.

hence,

only A and B will emit photoelectron.