English Medium Class 10 - CBSE Question Bank Solutions for Science

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?

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?

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.

Draw magnetic field lines produced around a straight current carrying conductor passing through a cardboard. How will the strength of the magnetic field change when the point where magnetic field is to be determined is moved away from the conductor?

At the time of short circuit, the electric current in the circuit ______.

Where does the metal aluminium, used in the thermit process, occurs in the reactivity series of metals?

Answer the following question.
What is the function of a galvanometer in a circuit?

Two electric bulbs rated 100 W; 220 V and 60 W; 220 V are connected in parallel to electric mains of 220 V. Find the current drawn by the bulbs from the mains.

Study the following circuit and find out:
      (i) Current in 12 Ω resistor.
      (ii) The difference in the readings of A₁ and A₂, if any.