Question

State how will you use physical balance to measure mass of an object. Mention three precautions that you should observe.

Answer 1

The physical balance or called as the beam balance was the first instrument which is used to measure the solid mass. It contains a pivoted horizontal lever having the same lengths of the arms. This is called as beam. It has two pans in which the standard weights and the solid substance is to be placed. The unknown mass is placed in the right pan and the standard pans are placed in the left pan, generally. We want to balance the beam so that the beam is completely horizontal. Now calculate the total mass of the standard weights and find out the mass of the unknown substance.

Precautions

i) The weights should be carried with forceps. They should not be carried with bare fingers to avoid the change in its weight due to the presence of moisture and dust particles.

ii) Wet and hot objects should not be kept on the pan.

iii) The beam should be lowered each time before adding or removing weights from the pan.