Question

A thermometer using Hg measures temperature because ...

Pick the answers that are appropriate.

		a) Mercury is liquid and expands its volume as it is heated
		b) Mercury is squeezed into a narrow column
		c) The expansion coefficient of glass is small compared to that of mercury
		d) The thermometer can be calibrated at the freezing and boiling temperatures of water.

Answer 1

Since most of the liquids expands its volume when it is heated but mercury expands more that is correct.But this is not mentioned in option a.

Thermal expansion is the tendency of matter to change in volume in response to a change in temperature, through heat transfer. higher the coefficient of thermal expansion, more sensitive is the material to change in temperature.

Mercury is used in thermometers because it has high coefficient of expansion. Hence, the slightest change in temperature is notable when it's used in a thermometer.

Expansion coefficient of glass should be less than mercury in order to measure small temperature fluctuations.

So option c is correct

also it does not stick to(wet) the capillary wall of the thermometers, and its easy to obtain in its elemental form.

So b is also correct. Option a may also be correct depends on the standard of book you are reading.