English Medium कक्षा १० - CBSE Question Bank Solutions for Science

If A, B, C, D, E, F, G, H, I, J and K represent metals in the decreasing order of their reactivity, which one of them is most likely to occur in a free state in nature?

Name a metal which does not react with cold as well as hot water but reacts with steam.

Name a metal which It does not react with any physical state of water?

When calcium metal is added to water, the gas evolved does not catch fire but the same gas evolved on adding sodium metal to water catches fire. Why is it so?

A zinc plate was kept in a glass container having CuSO₄ solution. On examining it was found that the blue colour of the solution is getting lighter and lighter. After a few days, when the zinc plate was taken out of the solution, a number of small holes were noticed in it. State the reason and give chemical equation of the reaction involved.

The change in focal length of an eye lens is caused by the action of the ______.

What are noble gases

What is the cause of chemical bonding (or chemical combination) of atoms of elements?

What is the characteristic of the electronic configuration of noble gases?

Define the following:

Reflex arc

Write the name and formula of a molecule made up of three atoms of oxygen.

Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of 1.5 V, 5 Ω, 10 Ω and 15 Ω resistors and a plug key, all connected in series.

Distinguish between an open and a closed circuit.

State the relation between work, charge and potential difference for an electric circuit.

Write a chemical equation to illustrate the use of aluminium for joining cracked railway lines.

In the Activity shown below, how do we think the displacement of rod AB will be affected if

1. current in rod AB is increased
2. a stronger horse-shoe magnet is used
3. length of the rod AB is increased?

What is the function of a split ring in an electric motor?

Nervous and hormonal systems together perform the function of control and coordination in human beings. Justify this statement with the help of an example.

Explain the following: 

Reactivity of aluminium decrease if it is dipped in nitric acid.

Answer the following question.
An electric lamp of resistance 20 Ω and a conductor of resistance 4 0 are connected to a 6 V battery as shown in the circuit. Calculate: 

(a) the total resistance of the circuit,  

(b) the current through the circuit, 

(c) the potential difference across the  (i) electric lamp and (ii) conductor, and

(d) power of the lamp.