Question

To start a car engine, the car battery moves 3.75×10²¹ electrons through the starter motor. How many coulombs of charge were moved?

Short answer

To start a car engine \({\rm{ - 600 C}}\) of charge were moved.

Step-by-step solution

Quantization of charge

According to quantization of charge, all charged objects in the nature are integral multiples of charge on electron or proton.

Coulombs of charge moved

The charge moved to start a car engine is calculated by using quantization of charge.

According to the quantization of charge,

Q = ne

Here, Q is the total charge moved, n is the number of electrons move to start a car engine $\left(n=3.75\times {10}^{21}\right)$ ,ande is the charge on electron \(\left( {{\rm{e = - 1}}{\rm{.6 \times 1}}{{\rm{0}}^{{\rm{ - 19}}}}{\rm{ C}}} \right)\).

Substituting all known values,

$$\begin{gathered} Q=\left(3.75\times {10}^{21}\right)\times \times \left(-1.6\times {10}^{-19}C\right) \\ =-600C \end{gathered}$$

Hence, to start a car engine -600 C of charge were moved.