Two stream of photons, possessing energies equal to twice and ten times the work function of metal are incident on the metal surface successively. The value of ratio of maximum velocities of the photoelectrons emitted in the two respective cases is x : y. The value of x is ___________.
Answer (integer)
1
Solution
$K{E_{\max }} = hv - \phi$<br><br>${1 \over 2}m{v^2} = hv - \phi$<br><br>$v = \sqrt {{{2(hv - \phi )} \over m}}$<br><br>Given $h{v_1} = 2\phi$<br><br>$h{v_2} = 10\phi$<br><br>$\therefore$ ${{{v_1}} \over {{v_2}}} = \sqrt {{{h{v_1} - \phi } \over {h{v_2} - \phi }}}$<br><br>$${{{v_1}} \over {{v_2}}} = \sqrt {{{2\phi - \phi } \over {10\phi - \phi }}} = {1 \over 3}$$ = ${x \over y}$
<br><br>$\therefore$ x = 1
About this question
Subject: Physics · Chapter: Dual Nature of Matter and Radiation · Topic: Photoelectric Effect
This question is part of PrepWiser's free JEE Main question bank. 145 more solved questions on Dual Nature of Matter and Radiation are available — start with the harder ones if your accuracy is >70%.