1. What are scalar quantities? Give example.
Physical quantities which have only the magnitude, but no direction are called the scalar quantities.
Example: Mass, Distance, Time, Volume, Speedetc..

2. What are Vector quantities? Give example.

The physical quantities which have magnitude as well as direction are called the vector quantities.
Example : Displacement, Velocity, Accelerationetc.

3. What you mean by least count of an instrument?
The least count of an instrument is the smallest measurement that can be taken accurately with it.

4. What is the least count of a vernier or vernier constant?
The least count of a vernier is equal to the difference between the values of one main scale division and one vernier scale division. Its also called vernier constant.

5. How the least count of vernier is obtained?
The least count of a vernier is obtained simply by dividing the value of one division of main scale by the total number of divisions on vernier scale.

6. What you mean by vernier calipers?
A vernier caliper is also called the slide calipers. It is used to measure the length of a rod, the diameter of a sphere, the internal and external diameters of a hollow cylinder, the depth of a small beaker etc.

7. What are the main parts of vernier calipers?
Outside jaws, inside jaws, strip, main scale and vernier scale.

8. What is zero error in vernier calipers? What are the different kinds of error?
The zero error is equal to the distance between the zero of the main scale and the zero of the vernier scale. Two kinds of zero error are there .
(i) Positive zero error
(ii) Negative zero error

9. What you mean by pitch of a screw?
The pitch of a screw is the distance moved by the screw along its axis in one complete rotation of its head.

10. What you mean by least count of a screw?

The least count of a screw is the distance moved by it is rotating the circular scale by one division.
    

11. What you mean by screw gauge?
A screw gauge is used to measure the diameter of a wire or thickness of a paper etc. usually to an accuracy of third decimal place of cm.

12. What are the main parts of screw gauge?
Ratchet, Sleeve, Thimble, Main scale, Circular scale.

13. What you mean by pitch and least count of a screw gauge?
Pitch of a screw gauge is the linear distance moved by its screw on the main scale when the circular scale is given one complete rotations. The least count of a screw gauge is the linear distance moved by its screw on the main scale when the circular scale is rotated by one division on it.

14. What you mean by volume and write its unit?
The space occupied by a body is called its volume. The SI unit of volume is cubic metre or m³. Its a big unit generally the volume of liquids is expressed in litre.

15. What you mean by a simple pendulum?
A simple pendulum is a heavy point mass suspended from a rigid support by a massless and inextensible string.