Question

The mass of an electron is 9.1 x 10 ^-28 gm and velocity 10^5cm/sec then KE?

Answer 1

Explanation:

Given:-

mass of electron is

$9.1 \times {10}^{ - 28} \: gm$

and

velocity of electron

$= 10 {}^{5} cm \: per \: sec$

Now ,

mass of electron in kg

$9.1 \times {10}^{ - 31}kg$

velocity of electron in m /s

$= 10 {}^{3} \: m \: \: per \: second$

we know that

$</em></strong><strong><em>K.E</em></strong><strong><em> </em></strong><strong><em> = \frac{1}{2}mv {}^{2}$

$K.E = \frac{1}{2} \times 9.1 \times {10}^{ - 31} \times (10 {}^{3} ){}^{2}$

$K.E = \frac{1}{2} \times 9.1 \times 10 {}^{ - 31} \times 10 {}^{6}$

$K.E = 4.55 \times {10}^{ - 25} joule$

hope it helps