1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V. The threshold frequency of the material is

A
2.5×1015 Hz
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
1.6×1015 Hz
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
5×1015 Hz
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
4×1015 Hz
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is B 1.6×1015 HzFor hydrogen atom the energy is given by En=−13.6n2 eV For ground state, n=1 ∴E1=−13.612=−13.6 eV For first excited state, n=2 ∴E2=−13.622=−3.4 eV The energy of the emitted photon when an electron jumps from first excited state to ground state is hν=E2−E1=−3.4 eV−(−13.6 eV)=10.2 eV Maximum kinetic energy, Kmax=eVs=e×3.57 V=3.57 eV According to Einstein's photoelectric equation Kmax=hν−ϕ0 where ϕ0 is the work function and hν is the incident energy ϕ0=hν−Kmax =10.2 eV−3.57 eV =6.63 eV Threshold frequency, ν0=ϕ0h=6.63×1.6×10−19 J6.63×10−34 Js=1.6×1015 Hz Hence, option (C) is correct.

Suggest Corrections
12
Join BYJU'S Learning Program
Related Videos
Technologies
PHYSICS
Watch in App
Explore more
Join BYJU'S Learning Program