Question

The temperature of the sun is measured with
(A) Platinum thermometer
(B) Gas thermometer
(C) Pyrometer
(D) Vapour pressure

Answer 1

Hint Pyrometer is used to measure the temperature of the sun. It measures my determining the radiation from the body whose temperature is measured. It compares brightness and takes colour variation to measure the temperature.

Complete step-by-step solution
1. Platinum Thermometer: Platinum Thermometer is a device which has a piece of platinum wire which determines the temperature by measuring electrical resistance of the wire. It’s principle of measurement is as the temperature changes, resistance of the platinum wire also changes. Its measurement range is between \[ - 200^\circ C\] and \[1000^\circ C\] .2. Gas Thermometer: Gas Thermometer is a thermometer which measures temperature when there is change in volume or pressure of the gas. These thermometers have a range from \[ - 183^\circ C\] to \[100^\circ C\] .
3. Pyrometer: Pyrometers are non-contact thermometers which are used to measure temperature of an object’s surface. This temperature depends on the radiation emitted from the object. The radiation can be either infrared or visible. It can measure temperature nearly up to \[4000^\circ C\] .
4. Vapour Pressure: There are vapour pressure thermometers that use pressure gauge to measure vapour pressure of a liquid. Range of these thermometers are from \[ - 183^\circ C\] .
As we know, the temperature of the sun is very high, so we cannot get close to it. Hence, we need such an instrument which measures the temperature without getting in contact with it.
So, a pyrometer can be used to measure the temperature of the sun.

Hence, the answer is option (C) pyrometer.

Note Pyrometer is also known as Infrared thermometer or Radiation Thermometer or Non-contact thermometer. There are different types of pyrometers such as Colour Pyrometer, High-speed Pyrometer etc.