CBSE EXAMINATION PAPER-2024
SCIENCE
(Solved)
General Instructions :
Read the following instructions carefully and follow them :
- This question paper contains 28 questions. All questions are compulsory.
- This question paper is divided into 4 sections.
- Section A – questions number 1 to 3 are case based questions
- Section B – questions number 4 to 14 are multiple choice questions
- Section C – questions number 15 to 22 are very short answer
- Section D – questions number 23 to 28 are short answer
- There is no overall choice given in the question paper. However, an internal choice has been provided in few questions.
- Use of calculator is NOT allowed.
Section A
(1) Find the cation and the anion present in Calcium sulphate.
[1 Marks](2) Identify the acid and base from which Sodium chloride is formed.
[1 Marks](3) Sodium chloride and washing soda both belong to the same family of salts. Justify this statement.
[2 Marks](4) Define the term pH scale. Name the salt obtained by the reaction of Potassium hydroxide and Sulphuric acid and give the pH value of its aqueous solution.
(1) Which of the cut pieces of the two Planaria could regenerate to form a complete organism?
[1 Marks](2) Give an example of another organism which follows the same mode of reproduction as Planaria.
[1 Marks](3) What is the meaning of ‘development’ in regeneration?
[2 Marks](4) Differentiate between regeneration and fragmentation.
When electric current flows in a purely resistive circuit, electrical energy gets fully converted into heat energy. The amount of heat produced (H) in the circuit is found to be directly proportional to (i) the square of current (I²), (ii) the resistance (R) of the conductor, and (iii) the time (t) for which current flows. In other words, H = I²Rt. Electrical devices such as an electric fuse, electric heater, electric iron, etc. are all based on this effect called heating effect of electric current.
(1) List two properties of electric fuse.
[1 Marks](2) List two properties of heating elements.
[1 Marks](3) Name the principle on which an electric fuse works and explain how a fuse wire is capable of saving electrical appliances from getting damaged due to accidentally produced high currents.
[2 Marks](4) The power of an electric heater is 1100 W. If the potential difference between the two terminals of the heater is 220 V, find the current flowing in the circuit. What will happen to an electric fuse of rating 5 A connected in this circuit?
Section B
Select from the following a process in which a combination reaction is involved:
Identify the correct statement about the following reaction
2H₂S + SO₂ →2H₂O + S:
Consider the following statements about homologous series of carbon compounds:
All succeeding members differ by a CH₂ unit.
Melting point and boiling point increase with increasing molecular weight.
The difference in molecular masses between two successive members is 16u.
C₂H₂ and C₃H₄ are NOT the successive members of alkene series.
Identify the mode of asexual reproduction in the following organism:
The maximum resistance of a network of five identical resistors of 1/5 Ω each can be:-
Study the I-V graph for three resistors of resistances R₁, R₂, and R ₃ and select the correct statement from the following:
Section C
Define the term absolute refractive index of a medium. A ray of light enters from vacuum to glass of absolute refractive index 1.5. Find the speed of light in glass. The speed of light in vacuum is 3×10⁸ m/s.
Section D
(1) Define the term power of accommodation of the human eye. Write the name of the part of the eye which plays a major role in the process of accommodation and explain what happens when the human eye focuses (i) on nearby objects and (ii) distant objects.
Draw a ray diagram to show the formation of a rainbow in the sky. On this diagram, mark A – where dispersion of light occurs, B – where internal reflection of light occurs and C – where refraction of light occurs. List two necessary conditions to observe a rainbow.
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