English Medium Class 10 - CBSE Important Questions for Science

What is pollination?

What is meant by a power of a lens? Define its SI unit. 

Draw the well-labelled diagram of the human excretory system

What is atmospheric refraction? Use this phenomenon to explain the following natural events:

Twinkling of stars

Draw diagrams to illustrate your answers.

Write Joule's law of heating.

Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity

2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid.

What is observed when a solution of sodium sulphate is added to a solution of barium chloride taken in a test tube? Write equation for the chemical reaction involved and name the type of reaction in this case.

The pH of a salt used to make tasty and crispy pakoras is 14. Identify the salt and write a chemical equation for its formation. List its two uses.

Define excretion.

Name the basic filtration unit present in the kidney.

Write a and b in the given flow chart of the neuron through which information travels as an electrical impulse.

A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in F₁ progeny?

A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens

A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.

Show how would you join three resistors, each of resistance 9 Ω so that the equivalent resistance of the combination is 

1) 13.5 

2) 6 Ω

Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason?

State significance of pollination.

Write one main difference between asexual and sexual mode of reproduction. Which species is likely to have comparatively better chances of survival – the one reproducing asexually or the one reproducing sexually? Give reason to justify your answer.

Define the power of a lens.