CBSE EXAMINATION PAPER-2025
SCIENCE
(Solved)
General Instructions :
Read the following instructions carefully and follow them :
- This question paper contains 31 questions. All questions are compulsory.
- This question paper is divided into 5 sections.
- Section A – questions number 1 to 2 are case based questions
- Section B – questions number 3 to 17 are multiple choice questions
- Section C – questions number 18 to 23 are very short answer
- Section D – questions number 24 to 28 are short answer
- Section E – questions number 29 to 31 are long 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) How does the uterus prepare itself to receive and nurture the growing embryo? Explain.
[1 Marks](2) Write the site of fertilization in human female.
[1 Marks](3) What happens when the egg is not fertilized?
[2 Marks](4) How does the developing embryo get nutrition from the mother’s blood ? Explain.
A person allowed a narrow beam of white light from the sun to enter a dark room through a small aperture and placed a glass prism in its path in such a manner that the beam falls on the face AB of the prism as shown in the figure.
A screen S is placed on the other side of the prism, facing AC. On turning the prism slowly, a beautiful band of colours is obtained on the screen. It is the spectrum of sunlight.
(1) State the reason for getting a band of seven colours in the above case.
[1 Marks](2) Name the phenomenon due to which a prism splits the incident white light into a band of colours.
[1 Marks](3) Explain with the help of a labelled ray diagram, an experimental arrangement to show the recombination of the spectrum of white light.
[2 Marks](4) Draw a labelled ray diagram to show the formation of a rainbow.
Section B
The correct balanced chemical equation showing exothermic reaction in which natural gas burns in air is:
The warning sign shown in the given figure must invariably be displayed/pasted on the containers which contain hydroxide of:
Two metals zinc and tin are dissolved separately in definite proportions in molten copper (the primary metal) to obtain two different alloys respectively known as:
If the absolute refractive indices of two media X and Y are 6⁄5 and 4⁄3 respectively, then the refractive index of Y with respect to X will be:
In the given figure the angle of incidence and the angle of deviation respectively are:
Identify from the following a group containing all non-biodegradable substances:
Assertion (A): Nichrome is an alloy which is commonly used in electrical heating devices such as electric irons, toasters, etc.
Reason (R): The resistivity of nichrome is high and its resistance decreases with increase in temperature.
Assertion (A): Animals will not get energy if they eat (consume) coal as food.
Reason (R): Specific enzymes are needed for the breakdown of a particular food.
Section C
Write one function each of the following, in a seed:
(i) Seed coat
(ii) Cotyledon
(iii) Radicle
(iv) Plumule
Out of the two lenses, one concave and the other convex, state which one will diverge a parallel beam of light falling on it. Draw a ray diagram to show the principal focus of the lens.
Write the main steps to culture yeast in the laboratory.
A ray of light after refraction from a convex lens emerges parallel to its principal axis.
(i) Draw a labelled ray diagram to show it.
(ii) In this case, the incident ray before refraction from the lens passes through a point on its principal axis. Name the point.
Section D
Write the electron-dot structures of (i) sodium, and (ii) oxygen. Using these structures, show the formation of sodium oxide. Mark the anion and cation present in this compound.
(At. No. – Sodium = 11 and Oxygen = 8)
(a) Define hormone.
(b) “Hormones should be secreted in precise quantities. We have a feedback mechanism through which this is done.” With the help of an example justify the statement.
The lowest part of the ear called earlobe, is closely attached to the side of the head in some of us (Figure ‘X’), and not in others, called free earlobe (Figure ‘Y’). Attached and free earlobes are two variants found in human populations. The gene for free earlobe is dominant over attached earlobes.
(a) A man with attached earlobes marries a woman having free earlobes. 50% of their children have free earlobes and 50% have attached earlobes. Explain the inheritance of this trait and write the trait combinations of the progeny.
(b) Write the gene combinations of the father and the mother in the above case.
Section E
(i) “The length of the small intestine in various animals depends on the food they eat.” Justify the statement.
(ii) Discuss the role of the pancreas and bile juice in the digestion of food in human beings.
(iii) How is the small intestine designed to absorb digested food ?
(i) State the role of rings of cartilage present in the throat.
(ii) Discuss the role of the ribs and diaphragm when air is taken in during the breathing cycle.
(iii) Why do we get muscle cramps during heavy exercise ? Explain.
(i) Define the term solenoid. Draw the pattern of the magnetic field lines in and around a current carrying straight solenoid. Mark on the pattern the (i) direction of current, (ii) direction of field lines near the ends of the solenoid, and (iii) region where the magnetic field is uniform.
(ii) How would you make an electromagnet using a current carrying solenoid ?
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