KCET2007PhysicsDual Nature of Matter
A and B are two metals with threshold frequencies 1.8 10¹⁴ ~Hz and 2.2 10¹⁴ ~Hz . Two identical photons of energy 0.825 eV each are incident on them. Then photoelectrons are emitted by (Take h=6.6 10⁻³⁴ ~J - s )
Options
- AB alone
- BA alone
- Cneither A nor B
- Dboth A and B
Correct answer
B. A alone
Step-by-step solution
Threshold energy of A is aligned E_ A &=h v_ A =6.6 10⁻³⁴ 1.8 10¹⁴ &=11.88 10⁻²⁰ ~J &= 11.88 10⁻²⁰ 1.6 10⁻¹⁹ eV =0.74 eV aligned Similarly, E_ B =0.91 eV Since, the incident photons have energy greater than E_ A but less than E_ B . So, photoelectrons will be emitted from metal A only.