English Medium Class 9 - CBSE Question Bank Solutions for Science

An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a frictionless horizontal table. The force required to keep this object moving with the same velocity is :

State whether the following statement is true or false :

Milk is a pure substance.

Name one metal and one non-metal which exist as liquids at room temperature.

In a cluster of hutments, many people are suffering from malaria. Mention the unhygienic conditions that must be prevailing in that locality. How does a doctor confirm malaria?

Name any three diseases of human beings caused by bacteria and three diseases caused by virus.

Explain how does the body react after the entry of microbe in the body.

Distinguish between symptoms and signs of a disease.

Write down the causal organisms of the following diseases :

Tuberculosis, Kala-azar, Malaria, Measles, Athlete's foot, Cholera.

Write short notes on

(a) AIDS;

(b) Malaria.

Describe certain bacterial diseases of human beings.

Give an account of some important viral diseases of human beings.

Write short notes on

(a) Tuberculosis;

(b) Polio.

Explain rain water harvesting.

How are clouds formed?

How is rain produced?

Name the scientist who discovered electron.

Which subatomic particle was discovered by : Thomson?

Name two sound absorbing materials (or objects) which can make our big room less echoey.