Home » mcq » physics » An electron and a proton starting from rest get accelerated through potential difference of 100 kV. The final speed of the electron and the proton are Ve and Vp respectively. Which of the following relations is correct? A. Ve > Vp B. Ve < Vp C. Ve = Vp D. Cannot be determined
[amp_mcq option1=”Ve > Vp” option2=”Ve < Vp" option3="Ve = Vp" option4="Cannot be determined" correct="option1"]
The correct answer is: A. Ve > Vp
The kinetic energy of a charged particle is given by the equation:
$KE = \frac{1}{2}mv^2$
where $m$ is the mass of the particle and $v$ is its speed.
The potential energy of a charged particle in an electric field is given by the equation:
$PE = qV$
where $q$ is the charge of the particle and $V$ is the potential
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difference.
When a charged particle is accelerated through a potential difference, its kinetic energy increases by an amount equal to its potential energy.
The mass of an electron is much less than the mass of a proton. Therefore, the kinetic energy of an electron that has been accelerated through a potential difference of 100 kV will be much greater than the kinetic energy of a proton that has been accelerated through the same potential difference.
Therefore, the speed of the electron will be much greater than the speed of the proton.
Option A is correct.