English Medium Class 9 - CBSE Question Bank Solutions for Science

The device which converts mechanical energy into energy which runs our microwave oven is :

A microphone converts :

Demonstrate the formation of convective currents.

Set up an experiment to measure gain and loss of heat by water, sand and air.

Name the scientist who gave law of constant proportions.

Name the scientist who gave atomic theory of matter.

Which postulate of Dalton's atomic theory is the result of law of conservation of mass given by Lavoisier ?

Which part of the Dalton's atomic theory came from the law of constant proportions given by Proust ?

Name any two laws of chemical combination.

Name the negatively charged particle present in the atoms of all the elements.

State whether the following statement is true or false :
The anode rays obtained from all the gases consist of positively charged particles called protons.

Give one major drawback of Dalton's atomic theory of matter.

Fill in the blank of the following statement :

The electron has _________ charge, the proton has _________ charge, and the neutron has _________ charge.

Why is an atom neutral inspite of the presence of charged particles in it?

Compare an electron, a proton and a neutron in respect of their relative masses and charges.

Compare an electron and a proton in respect of mass and charge.

Compare a proton and a neutron in respect of mass and charge.

State the location of electrons, protons and neutrons in an atom.

State the law of constant proportions. Give one example to illustrate this law.

State the various postulates of Dalton’s atomic theory of matter.