Question

Find the total electric charge of 2.5 kg of electrons. Express your answer using two significant figures.

Answer 1

Answer : The total electric charge of electrons is, $-4.4\times 10^{11}C$

Explanation:

Answer : The number of electrons transferred are, $4.68\times 10^{20}$

Explanation :

First we have to calculate the number of electrons.

Number of electrons = $\frac{\text{Total mass of electrons}}{\text{Mass of one electron}}$

Mass of 1 electron = $9.1\times 10^{-31}kg$

Total mass of electron = 2.5 kg

Number of electrons = $\frac{2.5kg}{9.1\times 10^{-31}kg}$

Number of electrons = $2.75\times 10^{30}$

Now we have to calculate the total electric charge of electrons.

Formula used :

$Q=ne\\\\n=\frac{Q}{e}$

where,

n = number of electrons transferred = $2.75\times 10^{30}$

Q = charge on electrons = ?

e = charge on 1 electron = $-1.602\times 10^{-19}C$

Now put all the given values in the above formula, we get:

$2.75\times 10^{30}=\frac{Q}{-1.602\times 10^{-19}C}$

$Q=-4.4\times 10^{11}C$

Thus, the total electric charge of electrons is, $-4.4\times 10^{11}C$