CBSE Sample Papers for Class 10 Science Paper 11
These Sample papers are part of CBSE Sample Papers for Class 10 Science. Here we have given CBSE Sample Papers for Class 10 Science Paper 11.
Time Allowed: 3 hours
Max. Marks: 80
General Instructions:
- The question paper comprises two sections, A and B. You are to attempt both the sections.
- All questions are compulsory.
- All questions of Section-A and B are to be attempted separately.
- There is an internal choice in three questions of three marks each, two questions of five marks each and one question
- (for assessing the practical skills) of two marks.
- Question numbers 1 and 2 in Section-A are one mark question. They are to be answered in one word or in one sentence.
- Question numbers 3 to 5 in Section- A are two marks questions. These are to be answered in 30 words each.
- Question numbers 6 to 15 in Section-A are three marks questions. These are to be answered in about 50 words each.
- Question numbers 16 to 21 in Section-d are five marks questions. These are to be answered in 70 words each.
- Question numbers 22 to 27 in Section- B are based on practical skills. Each question is a two marks question. These are to be answered in brief.
SECTION-A
Question 1.
How many molecules of water of crystallisation are there in
- Plaster of Paris,
- washing soda crystals?
Question 2.
Write the molecular formula of first two members of homologous series having functional group-Cl.
Question 3.
Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
Question 4.
List two biotic components of a biosphere.
Question 5.
Management of forest and wildlife resources is a very challenging task. Why? Give any two reasons.
Question 6.
- Give an example for a combination reaction which is exothermic.
- Identify the oxidising agent, reducing agent in the following reaction:
H2S + Cl2 → 2HCl + S - Name the phenomenon due to which the taste and smell of oily food changes when kept for a long time in open. Suggest one method to prevent it.
Question 7.
A reddish brown coloured metal, used in electrical wires, when powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas in passed over this black substance, it regains its original colour. Based on the above information answer the following questions.
- Name the metal and the black coloured substance formed.
- Write balanced chemical equations for both the reactions.
Question 8.
Two carbon compounds X and Y have the molecular formula C4H8 and C5H12 respectively. Which one of these is most likely to show addition reaction? Justify your answer. Also, give the chemical equation to explain the process of addition reaction in this case.
OR
Complete the following chemical equations:
(i) CH3COOC2H5 + NaOH →
(ii) CH3COOH + NaOH →
(ii) C2H5OH + CH3COOH \(\underrightarrow { Conc.H_{ 2 }SO_{ 4 } }\)
Question 9.
Explain how the human body responds when adrenaline is secreted into the blood.
OR
How does chemical coordination take place in animals?
Question 10.
Mention the total number of chromosomes along with the sex chromosomes that are present in a human female and a human male. Explain how in sexually producing organisms the number of chromosomes in the progeny remains the same as that of the parents.
Question 11.
“Natural selection and speciation leads to evolution.” Justify this statement.
Question 12.
A child while playing with his father’s spectacles burnt a hole in a piece of paper by focusing a small image of the sun on it.
- What defect of vision his father is suffering from?
- Write two causes for this defect.
- Draw a ray diagram to show image formation by the defective eye.
- Draw a ray diagram showing corrected eye using proper lens.
OR
A person cannot see objects beyond 80 cm from his eye while a person with normal eyesight can see object easily placed upto 160 cm from the eye. Find the nature, the focal length and the power of the correcting lens.
Question 13.
What is meant by overloading of an electrical circuit? Explain two possible causes due to which overloading may occur in household circuit. Explain one precaution that should be taken to avoid the overloading of domestic electric circuit.
Question 14.
- Shruti draws magnetic field lines close to the axis of a current carrying circular loop. As she moves away from the centre of circular loop, she observes that the lines keep on diverging. Explain the reason for her observation.
- Write two properties of magnetic field lines.
Question 15.
In a village people burn wood and cow dung as fuel for basic necessity. In another nearby village, people have a biogas plant in which biowaste is used to prepare biogas which is supplied to all the houses of the village.
Answer the following questions based on the situation given above.
- If we compare the situation of both villages, which practice is the best and why?
- What values are promoted by each village?
- Suggest some other ways that can be employed for saving resources?
Question 16.
- Identify the acid and the base whose combination forms the common salt that you use in your food. Write its formula and chemical name of this salt. Name the source from where it is obtained.
- What is rock salt? Mention its colour and the reason due to which it has this colour.
- What happens when electricity is passed through brine? Write the chemical equation for it.
OR
- Write the chemical name and chemical formula of washing soda.
- How is it obtained from sodium chloride? Give equations of the reactions.
- Why it is called a basic salt? Give its any one use.
Question 17.
An element placed in 2nd Group and 3rd Period of the Periodic Table, burns in presence of oxygen to form a basic oxide.
- Identify the element.
- Write the electronic configuration.
- Write a balanced equation when it burns in the presence of air.
- Write a balanced equation when this oxide is dissolved in water.
- Draw the electron dot structure for the formation of this oxide.
Question 18.
- List the sequence of events that occur during the process of photosynthesis.
- List the three kinds of blood vessels of human circulatory system and write their functions in tabular form.
Question 19.
- Write the functions of each of the following parts in a human female reproductive system:
- Ovary
- Uterus
- Fallopian tube
- Write the structure and functions of placenta in a human female.
Question 20.
- Define the following terms in the context of spherical mirrors:
- Pole
- Centre of curvature
- Principal axis
- Principal focus
- Draw ray diagrams to show the principal focus of a:
- Concave mirror
- Convex mirror
- Consider the following diagram in which M is a mirror and P is an object and Q is its magnified image formed by the mirror.
State the type of the mirror M and one characteristic property of the image Q.
OR
- Draw a ray diagram to show the formation of image by a convex lens when an object is placed in front of the lens between its optical centre and principal focus.
- In the above ray diagram mark the object-distance (u) and the image distance (v) with their proper signs (+ve or -ve as per the new Cartesian sign convention) and state how these distances are related to the focal length (s) of the convex lens in this case.
- Find the power of a convex lens which forms a real, and inverted image of magnification -1 of an object placed at a distance of 20 cm from its optical centre.
Question 21.
- Two identical resistors each of resistance 10 12 are connected in
- Series
- Parallel to a 6 V battery. Calculate the ratio of power consumed in the combination of resistors in two cases.
- Draw the circuit diagram of the two cases.
SECTION-B
Question 22.
Rahul adds aqueous solution of barium chloride to an aqueous solution of sodium sulphate. What would he observe?
Question 23.
A strip of copper was placed in a beaker containing zinc sulphate solution. On observing the strip next day, was there any colour change in the strip?
Question 24.
To prepare a good temporary mount of the petunia leaf peel showing many stomata, from where does the student has to get the peel?
OR
A student sets up the apparatus for the experiment to show that CO2, is released during respiration. After 2 hours, what would he observe?
Question 25.
Which of the following is not the correct diagram depicting budding in yeast?
Question 26.
A student carries out the experiment of tracing the path of a ray of light through a rectangular glass slab, for two different values of angle of incidence ∠i = 30° and ∠i = 45°. Find the set of values of the angle of refraction (∠r) and the angle of emergence (∠e), she is likely to observe in the two cases.
Question 27.
The following apparatus is available in a laboratory.
- Cell : Adjustable from 0 to 4.5 volt
- Resistors : 32 and 6 2
- Ammeters : Ay of Range () to 3 A; Least count 0.1 A A, of Range 0 to 1 A; Least count 0.05 A
- Voltmeters : V of Range 0 to 10 V; Least count 0.5 V V, of Range 0 to 5 V; Least count 0.1 V
Find the best combination of voltmeter and ammeter for finding the equivalent resistance of the resistors in series.
Answers
SECTION-A
Answers 1.
- \(\frac { 1 }{ 2 }\)
- 10
Answers 2.
CH3Cl, C2H5Cl
Answers 3.
The maximum accommodation of a normal eye is reached when the object is at a distance of 25 cm from the eye. The focal length of the eye lens cannot be decreased below this minimum limit. Thus, an object placed closer than 25 cm (or very close to eye) cannot be seen clearly by a normal eye.
Answers 4.
Producers, consumers, decomposers are the biotic components of a biosphere. (Any two)
Answers 5.
- Stakeholders of forest that are directly and indirectly dependent on them. Management of these resources has to take into account their interests, which is a challenging task.
- Industrialist which draw raw materials and government organisation which manage the forest are to be considered which is again a task.
Answers 6.
- Oxidising agent : Cl2
Reducing agent : H2S - Rancidity; it can be prevented by keeping food in airtight containers.
Answers 7.
- The metal is copper and the black coloured substance is copper oxide.
- 2Cu + O2 \(\underrightarrow { \triangle }\), 2CuO
CuO + H2 \(\underrightarrow { \triangle }\) Cu + H2O
Answers 8.
C4H8 will show addition reaction because it is an unsaturated hydrocarbon due to the presence of a double bond.
C4H8 + H2 \(\underrightarrow { Ni/Pd }\) C4H10
OR
- CH2COOC2H5 + NaOH = CH3 COONa + C2H5OH
- CH3COOH + NaOH — CH3COONa + H20
- C2H5OH + CH3COOH \(\underrightarrow { Conc.H_{ 2 }SO_{ 4 } }\) CH3COOC2H; + H2O
Answers 9.
On secretion of adrenaline into the blood, the heart beats faster, resulting in supply of more oxygen to our muscles. The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs. This diverts the blood to our skeletal muscles. The breathing rate also increases because of the contractions of the diaphragm and the rib muscles.
OR
In animals, chemical coordination is achieved through the agency of hormones which function as chemical messengers or informational molecules. Hormones are secreted in a very small amount by specialised tissues in the body called endocrine glands. These glands are ductless and pour their secretions directly into blood. Blood transports them to the target tissues or organs. Hormones in turn coordinate the activities of living organisms and also their growth. For example, pancreas secretes two hormones—insulin and glucagon.
Answers 10.
Human male – 22 pairs of chromosomes along with XY sex chromosome. Human female – 22 pairs of chromosomes along with XX sex chromosomes. The original number of chromosomes (the amount of DNA) becomes half during gamete formation. When the gametes from the male and female fuse during fertilisation, the original number of chromosomes (the amount of DNA) is restored in the progeny.
Answers 11.
Natural selection is defined as the change in frequency of some genes in a population, which gives survival advantage to a species whereas speciation is the development of a new species from pre-existing ones. This leads to a sequence of gradual changes in the primitive organisms over millions of years, to form newer species which are very different from older ones. This is called evolution. Thus we can say natural selection and speciation leads to evolution.
Answers 12.
- His father is suffering from hypermetropia.
- This defect arises because either if
- focal length of eye lens is too large, or
- the eyeball becomes too short
3.
4.
OR
The defect of vision is myopia.
Using the formula,
\(\frac { 1 }{ f } =\frac { 1 }{ \upsilon } =\frac { 1 }{ u }\)
Given, u = – 160 cm and y = – 80 cm
\(\frac { 1 }{ f } =-\frac { 1 }{ 80 } +\frac { 1 }{ 160 } =\frac { 1 }{ -1.60 }\)
ƒ = -160cm
Powe = \(\frac { 1 }{ f(in\quad metres) } =\frac { 1 }{ -1.60 }\)
= -0.625D
The -ve sign with f indicates the concave lens should be used for correction.
Answers 13.
Overloading of an electrical circuit happens when current increase abruptly and excessive heating takes place. Possible causes of overloading in household circuit are:
- When live wire comes in contact with neutral wire.
- Accidental hike in the supply voltage.
- Too many appliances are connected to a single socket leading to excessive heating and overloading.
Precaution to be taken: One should not connect too many appliances to the same socket or one should avoid live and neutral wire coming in contact by using proper insulation.
Answers 14.
- At every point of a current carrying circular loop the concentric circles representing the magnetic field around it would become larger and larger as we move away from the wire because field becomes weaker at larger distance.
-
- The direction of magnetic field lines is from North to South outside the bar magnet and from South to North inside the magnet.
- Magnetic field lines never intersect each other.
Answers 15.
- The practice of the second village is the best because they are employing a less polluting and less expensive way of fuel generation.
- The first village is showing ignorance and no concern for the environment, also there is no technological development. The second village on the other hand is promoting environmental concern, judicious use of resources and sharing.
- For saving resources, renewable sources of energy like CNG (Compressed Natural Gas) can be used in vehicles. Also, solar energy can be used in place of electricity.
Answers 16.
- Hydrochloric acid and sodium hydroxide forms the common salt NaCl, sodium chloride is its chemical name. It is obtained from sea water.
- Deposits of solid salt are found in several parts of the world. These large crystals are called rock salt. It is brown in colour due to the impurities.
- When electricity is passed through brine, sodium hydroxide is formed with the liberation of hydrogen and chlorine gas. 2NaCl + 2H2O , \(\underrightarrow { Electricity }\) , 2NaOH + Cl2 ↑ + H2 ↑
OR
- Chemical name — Sodium carbonate
Formula → Na2CO3.10H20 - NaCl + H2O + CO2 + NH3 → NH4Cl + NaHCO3
2NaHCO3 \(\underrightarrow { \triangle }\) Na2CO3 + CO2 1 + H2O
Na2 CO3 + 10H2O → Na2CO3.10H2O - It is a basic salt because when dissolves in water it gives a strong base NaOH.
Uses :- In glass, paper industry.
- As cleaning agent.
- For removing permanent hardness of water. (Any two)
Answers 17.
- Magnesium (Mg)
- K, L, M
2, 8, 2 - 2Mg(s) + 02(g) → 2MgO(s)
- MgO(s) + H7O(l) → Mg(OH)2 (aq)
Answer 18.
- Sequence of events during photosynthesis are:
- Absorption of light energy by chlorophyll.
- Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.
- Reduction of carbon dioxide to carbohydrates.
-
Blood vessels
Function
Arteries
They carry blood away from the heart to various organs pf the body Veins They collect the blood from different organs and bring it back to the heart
Capillaries
Exchange of material between the blood and surrounding cells takes place across the thin walls of capillaries
Answers 19.
- Following are the functions of mentioned parts:
- Ovary
- Production of female hormones such as estrogen or progesterone.
- Production of female gamete or egg or germ cells.
- Uterus
- Implantation of zygote or embryo.
- Nourishment of developing embryo.
- Fallopian tube
- Transfer of female gamete from the ovary.
- It is the site of fertilisation.
- Ovary
- Structure of placenta : It is a special disc-like tissue embedded in mother’s uterine wall and is connected to the foetus or embryo. It contains villi on the embryo’s side.
Functions of placenta : It provides a large surface area for glucose and oxygen to pass from mother to the embryo. It is also provides area for the nutrients to pass from mother’s body to the developing or developed embryo or foetus. It helps in passing the waste from the foetus or embryo to the mother’s body.
Answers 20.
-
- Pole is the centre of the reflecting surface of the mirror.
- Centre of curvature is the centre of the hollow sphere of which the reflecting surface of mirror forms a part.
- Principal axis is the straight line passing through the pole and the centre of curvature of a spherical mirror.
- Incident rays parallel to principal axis, after reflection, either converge to or appear to diverge from a fixed point on the principal axis called principal focus of the spherical mirror.
- (i)
(ii)
- M is a concave mirror and the image formed is erect virtual.
SECTION-B
Answers 22.
He would observe that a white precipitate is formed almost immediately.
This is because when aqueous solution of barium chloride is added to an aqueous solution of sodium sulphate, barium sulphate and sodium chloride are formed.
Answers 23.
On the next day, the copper strip remained as it was because zinc is more reactive than copper. So, copper was unable to displace zinc from its solution.
Answers 24.
The student has to get the peel from lower surface of the leaf because stomata are more numerous on the lower epidermis.
OR
He would observe the rise in water level in the beaker. This is because vacuum is created due to absorption of C0, by KOH which raises the water level.
Answers 25.
IV is not the correct diagram because in budding in yeast the bud appears as a protuberance.
Answers 26.
The angle of refraction must be less than angle of incidence. Also angle of emergence is equal to angle of incidence.
Answers 27.
Equivalent resistance, R = 3Ω + 6Ω = 9Ω
Maximum voltage to be measured = 4.5 V
Maximum current to be measured = \(\frac { V }{ R } =\frac { 4.5 }{ 9 } =0.5A\)
These requirements of measuring this current and voltage are fulfilled by ammeter A2 and voltmeter V2. Also these two instruments are more accurate due to their smaller least counts 0.05 A and 0.1 V respectively.
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