Question

an electron has kinetic energy of 15 EV calculates its velocity

Answer 1

Hi Mate!!

1 ev = 1.6 × 10 ^ -19 joule.

And

mass of e = 9.1 × 10 -31kg

Kinetic energy = 1 / 2 ( m ) ( v² )

=>. 1.6 × 10 ^ (-19) = 1/ 2 ( 9.1 × 10 ^( -31 ) kg × ( v²)


V = 5.92 × 10^5 m/s

Answer 2

Answer:

Velocity of the electron, $v=2.2\times 10^6\ m/s$

Explanation:

It is given that,

The kinetic energy of the electron is, K = 15 eV

We know that,

$1\ eV=1.6\times 10^{-19}\ J$

So, kinetic energy of the electron is, $K=2.4\times 10^{-18}\ J$

We need to find the velocity of the electron. The formula for kinetic energy is given by :

$K=\dfrac{1}{2}mv^2$

$v=\sqrt{\dfrac{2K}{m}}$

m is the mass of electron

$v=\sqrt{\dfrac{2\times 2.4\times 10^{-18}\ J}{9.1\times 10^{-31}\ kg}}$

v = 2296677 m/s

or

$v=2.2\times 10^6\ m/s$

So, the velocity of the electron is $2.2\times 10^6\ m/s$. Hence, this is the required solution.