Fluids — PHYSICS STD 9 — Question

(i) Parallel rays are incident:
1. on regular surface and
2. on irregular surface. In what respect do reflected rays in (1) differ from those of (2)?
(ii) Write down four characteristics of image formed in a plane mirror.

Draw velocity-time graph to show:
Zero acceleration
Write a sentence to explain the shape of graph.

It takes 0.2 s for a pendulum bob to move from the mean position to one end. What is the time period of the pendulum?

An object 10 cm high is placed at a distance of 20 cm in front of a spherical mirror of focal length 25 cm. By scale drawing find the nature, position, and magnification of the image in the following case:
Concave mirror

A boy is standing in front of a plane mirror at a distance of 3 m from it.
(i) What is the distance between the boy and his image?
(ii) If the boy moves 1 m backward, find the distance between the image and the boy.

Draw a neat diagram of a simple pendulum. Show on it the effective length of the pendulum and its one oscillation .

What is backlash error? Why is it caused? How is it avoided?

How do you measure the time period of a given pendulum? Why do you note the time for more than one oscillation?

(a) What are semiconductors? Name two semi conductors.
(b) What are doped semiconductors? Name two materials used for doping the semiconductors. What is the advantage of doping the semiconductors?