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

1.8 eV

1.1 eV

0.8 eV

1.6 eV

Solution

1.1 eV

mv =qBR
$KE subscript max space equals space fraction numerator open parentheses mv close parentheses squared over denominator 2 straight m end fraction space equals space 0. space 8 space eV hv space equals space 13.6 space open square brackets 1 fourth minus 1 over 6 close square brackets therefore space straight w space equals space hv minus KE subscript max space equals space 13.6 5 over 36 minus 0.8 space equals space 1.1 space eV$