Viva questions physics practical 1st year

Viva questions physics practical 1st year

1. Why is a spherometer so called?

Ans. It measures radius of curvature of spherical surfaces, hence it is called a spherometer.

Q2.Describe principle of a spherometer.

Ans. Its works on the principle of micrometer screw.

Q3. What is means by pitch of spherometer?

Ans. The pitch is the distance between two consecutive threads of the screw taken parallel to the axis of rotation or the

distance moved by the screw in one complete rotation of the circular scale.

Q4.How can the accuracy of a spherometer be increased?

Ans. Smaller is the L.C. is the accuracy of an instrument and vice –versa .The accuracy of the spherometer can be

increased by decreasing the pitch or by increasing the number of division of circular scale.

Q5. Can you measure the focal length of a lens?

Ans. Yes.

Q6. Why are the good spherometer made of gun metal?

Ans. To minimize wear and tear.

Q7.Define pitch of a spherometer?

Ans. Pitch of Spherometer is linear distance moved by its screw when the circular scale is given one complete rotation.

Q8.What is value of pitch of a common spherometer?

Ans. Generally it is 1mm.

Q9. What is least count of spherometer?

Ans. It is liner distance moved by the screw when it is rotated by one division of circular scale only.

Q10.The spherometer contains three legs, why?

Ans. Because it is the minimum number for stable equilibrium of the instrument .Moreover ,at least three points are

essential to describe a plane.