When a mercury-in-glass thermometer is placed in boiling water, ...

[khang]

When a mercury-in-glass thermometer is placed in boiling water, the mercury level falls slightly at first and then begins to rise. Explain this effect. If you have lab time, perform the experiment. Obtain the lab instructor's permission.

Question 2

Two wires A and B with circular cross sections are made of the same metal and have equal lengths, but the resistance of wire A is three times greater than that of wire B. What is the ratio of the radius of A to that of B?
  1.3
  2.3
  3.1
  4.1/3
  5.1/3

[rnehls]

Answer to Question 1

Because the mercury is enclosed in the glass bulb, the glass bulb is the first to
become hot and expand. The larger glass volume allows the mercury to fall. Once the
mercury itself begins to receive heat, it expands rapidly and rises again to the
maximum level.

Answer to Question 2

4