Structure of the Atom — Science STD 9 — Question

When a ball is thrown vertically upwards, its velocity goes on decreasing. What happens to its potential energy as its velocity becomes zero?

Even two or three crystals of potassium permanganate can impart colour to a very large volume of water. Which characteristic of particles of matter is illustrated by this observation?

Define the term ‘force’.

How is an ultrasound scan for fetus (unborn baby) better than X-ray?

What is the name if the device which is used to find the depth of sea (or ocean) by using ultrasonic sound waves?

When a crystal of potassium permanganate is placed in a beaker, its purple colour spreads throughout the water. What does this observation tell us about the nature of potassium permanganate and water?

A body does 1200 joules of work in 2 minutes. Calculate its power.

What is the time-period of a tuninh fork whose frequency is 200Hz?

Name the process which can be used to recover salt from and aqueous salt solution.