Question

Electrons are accelerated through a voltage difference of 120 kV inside a high voltage accelerator tube. What is the final kinetic energy of the electrons?

Answer 1

The final kinetic energy of the electrons is $1.92 \times 10^{-14}$

Explanation:

According to the Special Theory of Relativity, when a particle is in motion with a constant velocity, it is a substantial fraction of the speed of light. To describe the motion of the moving particle, Einstein's special theory of relativity is required.  

For the above-given question, it can be solved by using the below mention formula,

K = qV

where:

q is the charge

V is the potential difference

It is given that

V, Voltage difference is of 120 kV = $120 \times 10^{3} V$

q will be equal to e, q = e = $1.6 \times 10^{-19}$

$K=120 \times 10^{2} V \times 1.6 \times 10^{-19}=1.92 \times 10^{-14} J$