Page 16 - Physics - XI

VIVA VOCE

Q1. What is the utility of Vernier scale over the metre scale?
Ans. It increases the accuracy of the measurement.

Q2. How can we increase the accuracy of Vernier Callipers?
Ans. It can be increased by
(i) Increasing the number of divisions of a Vernier scale in the same length.
(ii) Decreasing the least count of the main scale.

Q3. What do you mean by accuracy?
Ans. It is the closeness of a measurement to the true value of the physical quantity.
Q4. What is meant by the least count of an instrument?
Ans. The least count of an instrument is the smallest value of the physical quantity which can be measured
accurately by the instrument.

Q5. Defi ne the least count of the Vernier Callipers.
Ans. It is the smallest distance which can be measured accurately by Vernier Callipers.
Least count = 1 M.S.D.–1 V.S.D.

Q6. What is a Vernier Calliper?
Ans. It is an instrument used to measure lengths of the order of fractions of millimetre accurately.
Q7. Why is it called Vernier Calliper?
Ans. It was invented by a French mathematician Pierre Vernier and hence it is called Vernier Calliper.

Q8. State the principle of Vernier Calliper.
Ans. If n divisions of Vernier scale coincide with (n – 1) divisions of the main scale, the diff erence
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between the magnitude of 1 M.S.D. and 1 V.S.D. is equal to M.S.D.

Q9. Explain Vernier constant. n
Ans. It is the diff erence between value of one main scale division and one Vernier scale division of a
Vernier Calliper.

Q10. Is there any diff erence between the least count and the Vernier constant of a Vernier Calliper?
Ans. No, the least count of a Vernier Calliper is known as Vernier constant.

Q11. What do you mean by error in the measurement?
Ans. The error in the measurement is equal to the diff erence between the true value and the measured
value of the quantity.

Q12. What is meant by zero error of Vernier Callipers?
Ans. If the zero of main scale does not coincide with the zero of the Vernier scale when the two jaws of
the Vernier Callipers are brought in contact, the instrument is said to have zero error.

Q13. What are the reasons or the occurrence of zero error?

Ans. It arises due to wear and tear of the instrument caused by its prolonged use. It can also arise due to
the faulty construction of the instrument.

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