Calculate the net charge on a substance con-

sisting of a combination of 1.9 × 10^13 protons
and 3.9 × 10^13 electrons.
Answer in units of C.

To calculate the net charge on a substance, we need to find the difference between the total number of protons and electrons. Protons have a positive charge while electrons have a negative charge. The unit of charge is coulombs (C).

First, let's calculate the total charge from protons and electrons separately:

Charge from protons = (number of protons) × (charge of a proton)
Charge from protons = (1.9 × 10^13 protons) × (1.6 × 10^-19 C/proton)

Charge from electrons = (number of electrons) × (charge of an electron)
Charge from electrons = (3.9 × 10^13 electrons) × (-1.6 × 10^-19 C/electron)

Now, let's calculate the net charge by subtracting the charge from electrons from the charge from protons:

Net charge = charge from protons - charge from electrons

Simplifying the equation:
Net charge = (1.9 × 10^13 protons) × (1.6 × 10^-19 C/proton) - (3.9 × 10^13 electrons) × (1.6 × 10^-19 C/electron)

By evaluating the above expression, you should get the net charge in units of coulombs (C).