### What is thermometry?

Thermometry The branch of heat relating to the measurement of the temperature of a body is called thermometry. The thermometer is an instrument used to measure the temperature of a body. The essential requisites of a thermometer are given as under:  1) Construction, 2) Calibration, and 3) Sensitiveness. For the construction of a thermometer, the proper choice of a substance, whose physical property varies uniformly with rising in temperature, is essential. 1) Construction The physical property of a substance plays an important role in the construction of a thermometer. In a mercury thermometer, the principle of expansion of mercury with rising temperature is used. The platinum resistance thermometer is based on the principle of the change in resistance with a change in temperature. The gas thermometer is based on the principle of change in volume or pressure with a change in temperature. 2) Calibration  When a thermometer is constructed, it should be properly calibrated. The standa

## What is work?

If because force-displacement happens then the product of force and component of displacement at the direction of force due to force is work.

Work is the product of applied force on a body and its displacement along the direction of a force.

Unit of work: J (Joule)

Dimension of work, [W] = ML2T-2

## What is Joule?

If due to the appliance of one-newton force at the direction of force the application point of force moves 1 meter then it is 1 joule of work.

## What is positive work?

If due to force the application point of force moves along the direction of force or the component of displacement is towards the direction of force then it is said to be work done by force or positive work.

## What is negative work?

If due to force the application point of force moves in the opposite direction of force or the component of displacement is at the opposite direction of force then it is said to be work done on force or negative work.

## What do you mean by the work 50 J?

The work measuring 50 J means 50 m of displacement of a body towards the direction of a force measuring 1 N. It further means 1 m of displacement of the body toward the direction of a force measuring 50 N.