Worksheet: Properties of Electric Charge

In this worksheet, we will practice converting between the SI unit of charge, the coulomb (C), and the number of electrons that this corresponds to.

Q1:

To start a car engine, the car’s battery moves 3.75×10 electrons through the starter motor. How many coulombs of charge are moved?

Q2:

Static electric charges are commonly measured in microcoulombs (µC) and in nanocoulombs (nC).

How many electrons are required to produce a charge of 2.00 nC?

  • A 9 . 8 1 × 1 0 electrons
  • B 8 . 6 8 × 1 0 electrons
  • C 1 . 0 8 × 1 0 electrons
  • D 1 . 1 9 × 1 0 electrons
  • E 1 . 2 5 × 1 0 electrons

How many electrons must be removed from an initially neutral object for the object to have a net charge of +0.500 µC?

  • A 1 . 3 4 × 1 0 electrons
  • B 3 . 1 2 × 1 0 electrons
  • C 4 . 8 2 × 1 0 electrons
  • D 8 . 2 8 × 1 0 electrons
  • E 2 . 1 1 × 1 0 electrons

Q3:

If 2.90×10 electrons move through a pocket calculator during a full day’s operation, how many coulombs of charge move through it?

Q4:

In an electric storm, a lightning bolt transfers electrons between some clouds and the ground. The total charge of these electrons is 65.0 C. How many electrons are transferred?

  • A 2 . 2 1 × 1 0
  • B 4 . 0 6 × 1 0
  • C 2 3 . 6 × 1 0
  • D 2 . 3 6 × 1 0
  • E 9 . 0 6 × 1 0

Q5:

A copper penny with a mass of 4.8 g is given a net positive charge of 4.0×10 C. To determine the change in the number of electrons in the penny during the charging process, use a value of 63.5 g/mol for the atomic mass of copper and a value of 29 for the atomic number of copper.

How many more protons than electrons are there in the atoms of the penny?

  • A 1 . 3 × 1 0
  • B 2 . 5 × 1 0
  • C 2 . 5 × 1 0
  • D 3 6 × 1 0
  • E 2 . 3 × 1 0

What is the ratio of the total number of electrons in the penny before the charging process to the number of electrons removed from the penny during the charging process?

  • A 1 . 0 × 1 0
  • B 1 5 × 1 0
  • C 3 . 6 × 1 0
  • D 5 . 3 × 1 0
  • E 3 6 × 1 0

Q6:

An amoeba contains 5.5×10 protons and has a net positive charge of 0.400 pC. What is the ratio of protons to electrons in the amoeba?

  • A 3 6 × 1 0
  • B 1 2 × 1 0
  • C 8 7 × 1 0
  • D 2 . 2 × 1 0
  • E 8 9 × 1 0

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