Physical Quantities and Measurements Short Questions

Question 41

How is negative zero error corrected in Vernier callipers?

Answer:
When the Vernier zero is to the left of the main-scale zero, the instrument reads less than the actual value. The magnitude of the negative zero error is added to the observed reading.

Question 42

What is a micrometer screw gauge used for?

Answer:
A micrometer screw gauge measures very small lengths, such as the diameter of a thin wire or the thickness of a metal sheet.

Question 43

Define the pitch of a micrometer screw gauge.

Answer:
Pitch is the distance moved by the spindle when the thimble completes one full rotation.

Question 44

How is the least count of a micrometer calculated?

Answer:
The least count equals the pitch of the screw divided by the number of divisions on the circular scale. A common micrometer has a least count of 0.01 mm.

Question 45

What is the function of the ratchet in a micrometer?

Answer:
The ratchet prevents excessive tightening and applies nearly uniform pressure to the object. It produces a clicking sound when the instrument is ready to be read.

Question 46

How is a micrometer reading calculated?

Answer:
The reading equals the main-scale reading plus the circular-scale reading multiplied by the least count. The appropriate zero correction is then applied.

Question 47

Differentiate between mass and weight.

Answer:
Mass is the quantity of matter in a body and is measured in kilograms. Weight is the gravitational force acting on the body and is measured in newtons.

Question 48

How does a physical balance measure mass?

Answer:
A physical balance compares the unknown mass of an object with known standard masses. Balance is achieved when the pointer remains at zero or oscillates equally on both sides.

Question 49

What is the least count of a mechanical and a digital stopwatch?

Answer:
A typical mechanical stopwatch has a least count of 0.1 s. A digital stopwatch may measure up to 0.01 s.

Question 50

What is a measuring cylinder?

Answer:
A measuring cylinder is a graduated glass or transparent plastic vessel used to measure the volume of liquids and non-dissolving solids.