Question

the mass of an electron is :

Answer 1

9.1×10^-31 kilograms

Answer 2

The mass of an electron is 9.1 * $10^{-31}$ kg

The mass of an electron proved to be very difficult to find in the early days. After a range of experiments were conducted by different scientists, the charge-to-mass ratio (e/m) of an electron was found. Later, the value of charge on the electron was discovered. Based on these two values, the mass of an electron was calculated and it is widely accepted today.