English Medium कक्षा १० - CBSE Question Bank Solutions for Science

Two metallic spheres A and B kept on insulating stands are in contact with each other. A positively charged  rod P is brought near the sphere A as shown in the figure. The two spheres are separated from each other,  and the rod P is removed. What will be the nature of charges on spheres A and B?

A metal sphere is kept on an insulting stands. A negatively charged rod is brought near it, then the sphere is  earthed as shown. On removing the earthing, and taking the negatively charged rod away, what will be the  nature of charge on the sphere? Give reason for your answer. 

Consider the sacle of voltmeter shown in the diagram and answer the following questions : 

(a) What is the least count of the voltmeter?

(b) What is the reading shown by the voltmeter ?

(c) If the voltmeter is connected across a resistor of 20 `Omega` how much current is flowing through the resistor?

A student wants to study a decomposition reaction by taking ferrous sulphate crystals. Write two precautions he must observe while performing the experiment. 

Answer the following question.
2 g of silver chloride is taken in a china dish and the china dish is placed in sunlight for some time. What will be your observation in this case? Write the chemical reaction involved in the form of a balanced chemical equation. Identify the type of chemical reaction.

State the relation correlating the electric current flowing in a conductor and the voltage applied across it. Also, draw a graph to show this. relationship.

Classify the following reaction into different type:

\[\ce{2KClO3(s)->[\Delta] 2KCl(aq) + 3O2(g)}\]

SI unit of resistance is:

The following reaction is used for the preparation of oxygen gas in the laboratory:

\[\ce{2KClO3_{(s)} ->[Heat] 2KCl + 3O2_{(g)}}\]

Which of the following statement about the reaction is correct?

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is:

Which one of the following processes involves chemical reactions?

Give the ratio in which hydrogen and oxygen are present in water by volume.

Which among the following statement(s) is (are) true?

Exposure of silver chloride to sunlight for a long duration turns grey due to

(i) the formation of silver by decomposition of silver chloride.

(ii) sublimation of silver chloride.

(iii) decomposition of chlorine gas from silver chloride.

(iv) oxidation of silver chloride.

Which of the following is an endothermic process?

When SO₂ gas is passed through a saturated solution of H₂S, which of the following reaction occurs?

Which of the following is not considered as crystalline allotrope of carbon?

Which of the following is not an allotropic form of carbon?

Reflex actions are mediated through ____________.

How many number of carbon atoms are joined in a spherical molecule of buckminsterfullerene?