SSLC (English Medium) Class 9 - Tamil Nadu Board of Secondary Education Question Bank Solutions for Science

State whether true or false. If false, correct the statement.

Distance covered by a particle never becomes zero but displacement becomes zero.

Assertion: Displacement of a body may be zero when distance travelled by it is not zero.

Reason: The displacement is the shortest distance between initial and final position.

Distinguish distance and displacement.

Exercise Problems.

An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 m and 20 s?

State whether true or false. If false, correct the statement.

The anode in electrolyte is negative.

The direction opposite to the movement of electron is called ______ current.

Assertion: Incident ray is directed towards the centre of curvature of spherical mirror. After reflection it retraces its path.

Reason: Angle of incidence (i) = Angle of reflection (r) = 0°

Why do some stars appear blue and some red?

You have just won a medal made of 22-carat gold. Have you just procured a pure substance or impure substance?

The number of neutrons present in  73Li is ______.

Calculate the number of neutrons, protons and electrons: 

1. atomic number 3 and mass number 7
2. atomic number 92 and mass number 238.

Modern periodic law states that the physical and chemical properties of elements are the periodic functions of their ______.

State whether true or false. If false, correct the statement.

Newlands’ periodic table is based on atomic masses of elements and modern periodic table is based on atomic number of elements.

State modern periodic law.

Covalent bond is formed by ______

Give the significance of pH of soil in agriculture.

Write any four uses of bases.

A phenomenon in which an element exists in different modification in same physical state is called ______.

Carbon forms large number of organic compounds due to ______.

______ is a suitable solven for sulphur.