Question

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

Answer 1

Hint: Define a physical balance and know its constituent parts. The condition for the physical balance is that after putting weights on both pans the beam should be horizontal. Write the precautions by analysing the measuring process.

Complete step by step answer:
A physical balance consists of a rigid beam in a pillar and on each side of the beam we have one pan where we can place the objects. The physical balance is also called the beam balance.

The beam is placed in the pillar in such a way that the pillar will be at the midpoint of the beam and the beam will be perfectly horizontal. On each side of the beam we have one pan.

We measure the mass of objects with the help of the standard mass. We can put the object with unknown mass in any one of the two pans and in the other pan we will put the standard masses to find the mass of the object by balancing the beam. If the mass on both sides of the beam are not equal the beam will not be completely horizontal. For the beam to be completely horizontal the mass on both sides of the beam should be equal and then we can find the mass of the object by calculating the total mass of the standard masses on the other pan. This way we can measure mass of an object using physical balance.

Three precautions we need to observe while using a physical balance when measuring –

(I)When we measure very small weights in the physical balance, we should not touch the standard masses. Because the presence of dust and moisture can change the original mass slightly.
(II)Each time before measuring the mass of any object the beam should be lowered, i.e. we should balance the beam without any ass.
(III)While measuring weights for high resolution, we should check the temperature of the room.

Note: We have many factors due to which we may get wrong results from a physical balance. Some of these factors are temperature, magnets, slope, vibrations, air drafts etc. when measuring with a physical balance keep in mind to check these factors.