20
practice examMultiple Choice

Practice Exam

Question 20 • Physics in the Universe

A neon light consists of a glass tube with metal wires at each end. When connected to a high-voltage source, the gas glows. If a fly lands on the glass tube, what will most likely happen?

Answer
A
The fly will not feel a shock because the glass conducts any free electrons back into the gas.
B
Electrons that are moving through the gas will be conducted through the glass and shock the fly.
C
The fly will not feel a shock because the glass insulates it from the electrons in the gas and the metal.
D
Electrons will flow directly from the metal wires along the glass and shock the fly.

Explanation

The electric current flows through the gas inside the tube, between the metal wires. Glass is an electrical insulator, so it does not let electrons in the gas or metal wires flow through to the fly on the outside. Therefore, the fly will not feel a shock.

AI-written and checked against the verified answer.

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