You all know that CBSE Board Exam is coming in February. So, I have brought CBSE Class 10 Science Important Questions 2024 which are being asked the same for last 3-4 years. Try to solve these questions for securing high marks in your board examination.
CBSE Important Questions: This question was asked continuously for 3 to 4 years.
1. Raina while doing certain reactions observed that heating of substance ‘X’ with vinegar like smell with a substance ‘Y’ (which is used as an industrial solvent) in presence of conc. Sulphuric acid on a water bath gives a sweet-smelling liquid ‘Z’ having molecular formula C4H8O2. When heated with caustic soda (NaOH), ‘Z’ gives back the sodium salt of and the compound ‘Y’. Identify ‘X’, ‘Y’, and ‘Z’. Illustrate the changes with the help of suitable chemical equations.
2. Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three pin plug, whereas an electric bulb can be connected with a two pin plug? She wrote: Three pin connections reduce heating of connecting wires.
(i) Is her answer correct or incorrect? Justify.
(ii) What is the function of a fuse in a domestic circuit?
3. The above image shows a thin lens of focal length 5m.
(1) What is the kind of lens shown in the above figure?
(ii) If a real inverted image is to be formed by this lens at a distance of 7m from the optical centre, then show with calculation where should the object be placed?
(iii) Draw a neatly labelled diagram of the image formation mentioned in
4. A piece of wire of resistance R is cut into three equal parts. These parts are then connected in parallel. If the equivalent resistance of this parallel combination is R₁, what is the value of the ratio R:R?
OR
Refer to the image below and state how the magnetic field pattern indicates regions where the magnetic field is stronger outside the magnet? What happens to the magnetic field when the current in the circuit is reversed?
5. Dil. HCl is added to Zn granules.” How will you prove that chemical change has taken place here? Support your response with two arguments.
6. State the post-fertilisation changes that lead to fruit formation in plants.
7. What is the purpose of making urine in the human body? Name the organs that stores and releases the urine.
OR
Why do arteries have thick and elastic walls whereas veins have valves?
8. Assertion: Biodegradable substances result in the formation of compost and natural replenishment. Reason: It is due to breakdown of complex inorganic substances into simple organic substances.
9. Assertion: A compass needle is placed near a current carrying wire. The deflection of the compass needle decreases when the magnitude of the current in the wire is increased. Reason: The strength of a magnetic field at a point near the conductor increases on increasing the current.
10. Aaaaaaa: Study the food chain given below and answer the questions that follow:
(a) If the amount of energy available at the third trophic level is 100 joules, then how much energy will be available at the producer level? Justify your answer.
(b) Is it possible to have 2 more trophic levels in this food chain just before the fourth trophic level? Justify your answer.
CBSE Important Objective Questions 2024
1. Height of a plant is regulated by:
(a) DNA which is directly influenced by growth hormone.
(b) Genes which regulate the proteins directly.
(c) Growth hormones under the influence of the enzymes coded by a gene.
(d) Growth hormones directly under the influence a gene.
2. An object is placed in front of a convex mirror. Its image is formed:
(a) at a distance equal to the object distance in front of the mirror.
(b) at twice the distance of the object in front of the mirror.
(c) half the distance of the object in front of the mirror.
(d) behind the mirror and it’s position varies according to the object distance.
3. When light enters the atmosphere it strikes on extremely fine particles, which deflect the rays of light in all possible directions, This is due to –
(a) reflection of light.
(b) atmospheric refraction.
(c) scattering of light.
(d) dispersion of light.
4. Which of the following features relates to biodegradable substances?
(a) Broken down by biological processes.
(b) Remain inert.
(c) Persist in environment for long time.
(d) May harm the ecosystem.
5. A farmer wants to grow banana plants genetically similar enough to the plants already available in his field. Which one of the following methods would you suggest for this purpose?
(a) Regeneration
(b) Budding
(c) Vegetative propagation
(d) Sexual reproduction
6. Identify the product which represents the solid state in the above reaction.
(a) Barium chloride.
(b) Barium sulphate.
(c) Sodium chloride.
(d) Sodium sulphate.
7. Generally food is broken and absorbed within the body of organisms. In which of the following organisms is it done outside the body?
(a) Amoeba
(b) Mushroom
(c) Paramoecium
(d) Lice
8. An element ‘M’ has 50% of the electrons filled in the 3d shell as in the 2nd shell. The atomic number of ‘M’ is:
(a) 10
(b) 12
(c) 14
(d) 18
9. On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colourless gas is produced when a burning match stick is brought near it. Which of the following correctly represents metal ‘X’?
(a) Sodium.
(b) Sulphur.
(c) Copper.
(d) Silver.
10. The colour of the solution observed after 30 minutes of placing zinc metal to copper sulphate solution is
(a) Blue
(b) Colourless
(c) Dirty green
(d) Reddish Brown
