What is meant by zero error of a vernier callipers ? How is it determined ? Draw neat diagrams to explain it. How is it taken in account to get the correct measurement ?

What do you mean by zero error of a screw gauge ? How is it accounted for ?

Define least count of a vernier callipers. How do you determine it?

Draw a neat labelled diagram of a vernier callipers.

A vernier callipers has a zero error + 0.06 cm. Draw a neat labelled diagram to represent it.

What is full form of AIDS? How is it transmitted? Draw a labelled diagram of HIV.

What is meant by long-sightedness? How can this defect be corrected ?

Name the two scales of a vernier callipers and explain, how it is used to measure a length correct up to 0.01 cm.

If we measure a length l=6.24 cm with the help of a vernier callipers, then (a) What is least count of vernier callipers? (b) How many significant figures are there in the measured length? (c) Which digits are absolutely correct and which is/are doubtful?

Draw a diagram of a sweat gland. Explain how sweat is formed and expelled through the skin.

What is meant by colloid and colloidal state? How does the theory of selective adsorption explain the origin of charge on colloidal particles ?