An $\alpha$ particle and a proton are accelerated from rest through the same potential difference. The ratio of linear momenta acquired by above two particles will be:
Solution
<p>We know,</p>
<p>Momentum $(p) = \sqrt {2m{E_k}}$</p>
<p>and ${E_k} = q{V_{acc}}$</p>
<p>$\therefore$ $p = \sqrt {2mq\,{V_{acc}}}$</p>
<p>Both $\alpha$ particle and proton are passed through same potential difference.</p>
<p>$\therefore$ ${\left( {{V_{acc}}} \right)_\alpha } = {\left( {{V_{acc}}} \right)_p} = v$</p>
<p>$\therefore$ ${p_\alpha } = \sqrt {2{m_\alpha }{q_\alpha }v}$</p>
<p>${p_p} = \sqrt {2{m_p}{q_p}v}$</p>
<p>$\therefore$ $${{{p_\alpha }} \over {{p_p}}} = \sqrt {{{{m_\alpha }{q_\alpha }} \over {{m_p}{q_p}}}} $$</p>
<p>$= \sqrt {{{4{m_p} \times 2e} \over {{m_p} \times e}}}$</p>
<p>$= \sqrt {{8 \over 1}}$</p>
<p>$= {{2\sqrt 2 } \over 1}$</p>
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%.