question_answer

The radiation corresponding to \[3\to 2\]transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of \[3\times {{10}^{-4}}T.\]If the radius of the largest circular path followed by these electrons is 10.0 mm, the work function of the metal is close to: [JEE MAIN 2014]

A) 0.8 eV

B) 1.6 eV

C) 1.8 eV

D) 1.1 eV

Correct Answer: D

Solution :

[d]

[E = electron’s K.E.] [m = electron mass, e = electron charge]

photon energy = 1.9 eV.