List of top Questions asked in CBSE Class X

Give one example each of a unisexual flower and a bisexual flower. Mention the changes which a flower undergoes after fertilization.
Write one function each of the parts - (i) petals (ii) anther (iii) style and (iv) ovary of a bisexual flower.
Give two methods used to grow rose and jasmine plants by vegetative propagation.
What is asexual reproduction? Explain the process of budding in Hydra.
Name the method by which Amoeba and Leishmania reproduce. Write a major difference in the way they divide to produce new individuals.
Why can't two magnetic field lines cross each other? Draw magnetic field lines showing the direction of the magnetic field due to a current-carrying long straight solenoid. State the conclusion which can be drawn from the pattern of magnetic field lines inside the solenoid. Name any two factors on which the magnitude of the magnetic field due to this solenoid depends.
What are magnetic field lines? How is the direction of magnetic field at a point determined? Draw the pattern of magnetic field lines of the magnetic field produced by a current-carrying circular loop. Mark on it the direction of (i) current and (ii) magnetic field lines. Name the two factors on which the magnitude of the magnetic field due to a current-carrying coil depends.
What do the symbols given below represent in an electric circuit? Write one function of each.
Symbol of an Ammeter
Explain the statement "Potential difference between two points is 1 volt".
Determine the focal length of the lenses used in the spectacles.
List two causes of this defect.
A person uses lenses of power -0.5 D in his spectacles for the correction of his vision. (a) Name the defect of vision the person is suffering from.
Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood to the human heart. Also name that chamber of the heart which receives deoxygenated blood and state how deoxygenated blood from this chamber is sent to lungs for oxygenation.
"Some animals rely on environmental cues for sex determination." Justify this statement giving an example.
Write chemical equations to show what happens when an acid reacts with a:
Write chemical equations to show what happens when an acid reacts with a:
(i) Metal
(ii) Base
(iii) Carbonate
Write the name of the main product formed in each case
Explain why respiration is considered an exothermic reaction. Give the chemical equation for this reaction.
Write the percentage of the energy of sunlight captured by green plants, to convert it into food energy. Explain the fate of this energy when green plants are eaten by primary consumers.
A doctor finds in one of his patients that he is not maintaining a proper posture and balance of his body. State the region of brain and also the part of brain which is responsible for it.
How is the brain protected in our body?
Explain the mechanism of inheritance used by sexually reproducing organisms to ensure the stability of DNA of the species.
"Proteins control the expression of various characters." Explain this statement by taking an example of "tallness" as a characteristic in plants.
What is a rainbow? 'We see a rainbow in the sky only after the rainfall.' Why?
'Danger' signal lights are red in colour.
The sky appears dark to passengers flying at very high altitude
Express the refractive index of Medium 2 with respect to Medium 1 in terms of the speed of light in both media.
path of a ray of light going from Medium 1 to Medium 2