Which of the following is the correct device for the detection of thermal radiation
Constant volume thermometer
Liquid-in-glass thermometer
Six's maximum and minimum thermometer
Thermopile
A thermopile is a sensitive instrument, used for detection of heat radiation and measurement of their intensity.
The radiation 'P' is founded by a proper device on the bulb of a thermometer. Mercury in the thermometer shows a rapid increase. Name the radiation P.
A radiation P is focused by a proper device on the bulb of a thermometer. Mercury in the thermometer shows a rapid increase. The radiation P is :
(a) infrared radiation
(b) visible light
(c) ultraviolet radiation
(d) X -rays.