If that charge is 3.7 μC , by what percentage does the mass of a 31 g comb change during charging?

To calculate the percentage change in mass during charging, we need to first determine the change in mass caused by the charge and then calculate the percentage change.

The change in mass is related to the charge by Einstein's famous equation E=mc^2, where E is the energy, m is the mass, and c is the speed of light.

Here's how to calculate the change in mass:

1. Determine the energy associated with the charge. Energy is given by the formula E = qV, where q is the charge and V is the voltage.
- In this case, the charge q is given as 3.7 μC (microcoulombs). Convert it to coulombs by dividing by 10^6: 3.7 μC = 3.7 x 10^-6 C.
- The voltage V is not given, so let's assume it is 1 volt for simplicity.

Therefore, the energy E associated with the charge is: E = (3.7 x 10^-6 C) x (1 V) = 3.7 x 10^-6 J (joules).

2. Use Einstein's equation to calculate the change in mass. Rearrange the equation to solve for mass (m): m = E / c^2.
- The speed of light c is a constant value: c ≈ 3 x 10^8 m/s.

Therefore, the change in mass Δm is: Δm = (3.7 x 10^-6 J) / (3 x 10^8 m/s)^2.

3. Calculate the percentage change in mass using the formula: (Δm / initial mass) x 100.
- The initial mass is given as 31 g (grams). Convert it to kilograms by dividing by 1000: 31 g = 0.031 kg.

Therefore, the percentage change in mass is: (Δm / 0.031 kg) x 100.

By following these steps and plugging in the values, you can find the percentage change in mass during charging. Note that the voltage was assumed to be 1 volt for simplicity, so the result will be an approximation.