Improvement In Food Resources — Science STD 9 — Question

Define the ‘frequency’ and ‘time-period’ of a wave. What is the relation between the two?

What is the maximum number of electrons which can be accommodated in the:
Innermost shell of an atom?

Write down three unique characteristics of storage structure.

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

What is meant by the term chemical formula?

Which method is mostly used for purification of solids?

Name the unit in which the radius of an atom is usually expressed.

What are the three general classes of matter? Give one example of each type.

State whether the following statement is true or false:
Earth moves round the sun with uniform velocity.