Question

two students are experimenting with two neutral objects - a glass beaker and a sample of animal fur. they rub the two together and the glass beaker becomes charged positively and the fur becomes charged negatively. complete the analysis of this situation.

before

#p⁺ = #e⁻
#p⁺ > #e⁻
#p⁺ < #e⁻

#p⁺ = #e⁻
#p⁺ > #e⁻
#p⁺ < #e⁻

after

#p⁺ = #e⁻
#p⁺ > #e⁻
#p⁺ < #e⁻

#p⁺ = #e⁻
#p⁺ > #e⁻
#p⁺ < #e⁻

how did the beaker become charged?

electrons were added to it.
protons were added to it.
electrons were removed from it.
protons were removed from it.

Explanation:

• Before rubbing: Both the glass beaker and the animal fur are neutral. For a neutral object, the number of protons (\(\#p^{+}\)) is equal to the number of electrons (\(\#e^{-}\)), so for both the beaker and the fur before rubbing, \(\#p^{+}=\#e^{-}\).
• After rubbing: The glass beaker is positively - charged. A positive charge means that the number of protons is greater than the number of electrons (\(\#p^{+}>\#e^{-}\)), and the fur is negatively - charged, which means \(\#p^{+}<\#e^{-}\).
• Regarding how the beaker became charged: Protons are located in the nucleus of an atom and are not easily transferred during a simple rubbing (triboelectric) process. Electrons are more mobile. When the beaker becomes positively charged, it is because electrons (\(e^{-}\)) were removed from it.

Answer:

• Before: For the beaker \(\#p^{+}=\#e^{-}\), for the fur \(\#p^{+}=\#e^{-}\)
• After: For the beaker \(\#p^{+}>\#e^{-}\), for the fur \(\#p^{+}<\#e^{-}\)
• How the beaker became charged: Electrons were removed from it.