Question

Energy of an electron moving in 0.9c

Answer 1

According to Einstein's Mass energy equivalent equation E = m . c ^2

As we know mass of electron is- 9.1 × 10^(-31)

and c is speed of light i.e 3× 10^(8)

so energy will be equal to { 9.1 × 10^(-31) } × {0.9 × 3×10^(8)}^2

= 6.63 × 10^ (-14) joules