Question

An electron has an initial speed of


`4.2 * 10^5`
if it undergoes an acceleration of

`1.9 * {10}^(4)`
how long will it take to reach a speed of

`6.34 * {10}^(5)`

Answer 1

We use the equation of motion,

`v=u+at`

Here, v is final velocity, u is initial velocity, t is time taken and a is acceleration.

Given,
`v= 6.34*10^5 m/s, u=4.2 *10^5 m/s` and
`a = 1.9 *10^4 m/s^2` .

Substituting these values in above equation , we get

`6.34*10^5 m/s=4.2 *10^5 m/s+1.9 *10^4 m/s* t \\\\t=(2.14 *10^5 m/s)/(1.9 *10^4 m/s^2) =11.2\ s`

Therefore, time taken by an electron to reach the given final speed is 11.2 s.