Worksheet: Charging by Induction

In this worksheet, we will practice determining the net charge resulting from unequal amounts of positive and negative charges acquired by induction.


Suppose a speck of dust in an electrostatic precipitator has 1.00×10 protons in it and has a net charge of 5.00 nC. How many electrons does the speck of dust contain? The magnitude of the charge of protons and of electrons is 1.60×10 C.

  • A1.03×10e
  • B1.03×10e
  • C1.32×10e
  • D3.12×10e
  • E3.12×10e


Determine how many coulombs of positive charge are contained in a lump of pure plutonium with a mass of 4.00 kg. Use a value of 244 g/mol for the atomic mass of plutonium and recall that the plutonium has an atomic number of 94.

  • A1.61×10 C
  • B1.49×10 C
  • C1.90×10 C
  • D1.76×10 C
  • E2.03×10 C


A copper atom has 29 protons and a neutral ball of copper has one electron per proton. Copper has an atomic mass of 63.5 unified atomic mass units. A unified atomic mass units is equivalent to 1.66×10 g.

How many electrons would be contained in a neutral copper ball with a mass of 50.0 g?

  • A4.74×10
  • B3.06×10
  • C1.63×10
  • D1.38×10
  • E1.11×10

A copper ball with a mass of 50.0 g has a net charge of +2.00 µC. What percent of the electrons in the copper ball have been removed?

  • A1.37×10%
  • B9.68×10%
  • C7.19×10%
  • D8.20×10%
  • E9.09×10%


A copper penny of mass 2.500 g is given a net charge of 2.000×10 C.

The charge of an electron is 1.6021×10 C.

How many excess electrons are on the penny?

  • A1.271×10e
  • B1.226×10e
  • C1.316×10e
  • D1.295×10e
  • E1.248×10e

By what percent do the excess electrons change the mass of the penny?

  • A5.210×10%
  • B4.728×10%
  • C5.114×10%
  • D4.543×10%
  • E4.911×10%

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