CBSE Sample Papers for Class 10 Science Paper 9
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 9.
Time Allowed: 3 hours
Max. Marks: 80
- 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.
Tap water conducts electricity whereas distilled water does not. Why?
An organic compound burns with a sooty flame. Is it a saturated or an unsaturated compound?
Explain why the planets do not twinkle.
Select the biodegradable items from the list given below. Polythene bags, old clothes, wilted flowers, pencil shavings, glass bangles, bronze statue, vegetable peels.
How did the ‘Chipko Andolan’ ultimately benefit the local population? Give any two benefits.
Answer the following:
- Why is Plaster of Paris written as CaSO H2O? How is it possible to have half a water molecule attached to CaSO4?
- Why is sodium hydrogencarbonate an essential ingredient in antacids.?
- When electricity is passed through an aqueous solution of sodium chloride, three products are obtained. Why is the process called chlor-alkali?
A student dropped few pieces of marble in dilute hydrochloric acid contained in a test tube. The evolved gas was passed through lime water. What change would be observed in lime water? Write balanced chemical equations for both the changes observed.
Explain the following statements:
- Most metal oxides are insoluble in water but some of these dissolve in water. What are these oxides and their solutions in water called?
- At ordinary temperature, the surface of metals such as magnesium, aluminium and zinc, etc. is covered with a thin layer. What is the composition of this layer? State its importance.
- Some alkali metals can be cut with a knife.
Give reason why carbon can neither form C4+ cations nor C4- anions, but forms covalent compounds which are bad conductors of electricity and have low melting and boiling points.
1. What does the given experimental set-up demonstrate?
- Label the two parts indicated by question marks and labelled 1 and 2 in the above diagram.
- Suggest a suitable caption or heading for the above diagram.
What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
The genotype of green-stemmed tomato plants is denoted as GG and that of purple-stemmed tomato plants as gg. When these two are crossed,
- What colour of stem would you expect in their F1 progeny?
- Give the percentage of purple-stemmed plants if F1 plants are self pollinated.
- In what ratio would you find the genotypes GG and Gg in the F2 progeny?
In one of his experiments with pea plants Mendel observed that when a pure tall pea plant is crossed with a pure dwarf pea plant, in the first generation, F1 only tall plants appear.
- What happens to the traits of the dwarf plants in this case?
- When the F1 generation plants were self-fertilised, he observed that in the plants of second generation, F2 both tall plants and dwarf plants were present. Why it happened? Explain briefly.
A beam of white light falling on a glass prism gets split up into seven colours marked 1 to 7 as shown in the diagram. A student makes the following statements about the spectrum observed on the screen.
- The colours at positions marked 3 and 5 are similar to the colour of the sky and the core of a hard boiled egg respectively. Is the above statement made by the student correct or incorrect? Justify.
- Which two positions correspond closely to the colour of
- a solution of potassium permanganate?
- ‘danger’ or stop signal lights?
Describe the formation of rainbow in the sky with the help of a diagram.
Explain the meaning of the word “electromagnetic’ and `induction’ in the term electromagnetic induction. On what factors does the value of induced current produced in a circuit depend? State one practical application of this phenomenon in everyday life.
Why does a current carrying conductor kept in a magnetic field experience force? On what factors does the direction of this force depend? Name and state the rule used for determination of direction of this force.
Ramu has a piece of agricultural land in a village. He decides to set up a brick factory on it. His friend Shyam persuades him to change his decision in the interest of village because presence of a factory would severely affect the health of villagers as well as agricultural produce of others. Ramu understands and abandons his plans.
- Mention the values exhibited by Shyam.
- Explain how these values helped Shyam to save interests of his village.
- A dry pallet of common base ‘X’, when kept in open air absorbs moisture and turns sticky. The compound is also a by-product of chlor-alkali process. Identify ‘X’. What type of reaction occurs when ‘X’ is treated with strong acid? Write a balanced chemical equation for such reaction.
- Can we store the base ‘X’ in an aluminium container? Give reason in support of your answer.
Give suitable reason for the following statements:
- Rain water conducts electricity but distilled water does not.
- We feel burning sensation in the stomach when we overeat.
- A tarnished copper vessel regains its shine when rubbed with lemon.
- The crystals of washing soda change to white powder on exposure to air.
- An aqueous solution of sodium chloride is neutral but an aqueous solution of sodium carbonate is basic.
In the following table, six elements A, B, C, D, E and F of the modern periodic table with atomic numbers 3 to 18 are given:
- Which of these is
- Noble gas
- Which of these is the most active metal in 3rd period?
- Identify the most electronegative element in the third period.
- In the compound between B and F what type of bond will be formed?
- What would be the nature of oxide formed by C?
- It was observed that the leaves of a plant started getting wilted. Name the tissue which might have blocked. State the role of this tissue in plants.
- Explain opening and closing of stomata with the help of labelled diagrams.
- Name the physical phenomenon by which exchange of gases occur between plant body and atmosphere.
- Name the organ that produces sperms as well as secretes a hormone in human males. Name the hormone it secretes and write its functions.
- Name the parts of the human female reproductive system where fertilisation occurs..
- Explain how the developing embryo gets nourishment inside the mother’s body.
Analyse the following observation table showing variation of image distance (v) with object distance (u) in case of a convex lens and answer the questions that follow, without doing any calculations:
- What is the focal length of the convex lens ? Give reason in support of your answer.
- Write the serial number of that observation which is not correct. How did you arrive at this conclusion ?
- Take an appropriate scale to draw ray diagram for the observation at S. No. 4 and find the approximate value of magnification.
- To construct a ray diagram we use two rays which are so chosen that it is easy to know their directions after reflection from the mirror. List two such rays and state the path of these rays after reflection in case of concave mirrors. Use these two rays and draw ray diagram to locate the image of an object placed between pole and focus of a concave mirror.
- A concave mirror produces three times magnified image on a screen. If the object is placed 20 cm in front of the mirror, how far is the screen from the object?
- The electric power consumed by a device may be calculated by using either of the two expressions P = I2R or P = . The first expression indicates that it is directly proportional to R whereas the second expression indicates inverse proportionality. How can the seemingly different dependence of P on R in these expressions be explained?
- Explain the following:
- Why is tungsten used almost exclusively for filament of electric lamps?
- Why are copper and aluminium wires usually used for electricity transmission?
What happens when ferrous sulphate crystals are heated?
Iron filings were added to a solution of copper sulphate. After 10 minutes, it was observed that the blue colour of the solution changes and a layer gets deposited on iron filings. What is the colour of the solution and the layer deposited?
Which light influences the opening of stomata?
In the slides showing binary fission in Amoeba and budding in yeast, what is it observed?
Study the ray diagram given below and answer the following questions:
- State the type of lens used in the figure.
- List two properties of the image formed.
- In which position of the object will the magnification be – 1?
A student obtains a blurred image of an object on a screen by using a concave mirror. In order to obtain a sharp image on the screen, in which direction he will have to shift the mirror?
Plot a graph which shows the dependence of current Ion potential difference V across a resistor R.
Tap water contains dissolved salts and minerals which ionise in water and these ions conduct electricity. Distilled water do not contain salts and minerals and hence it does not conduct electricity.
The planets are much closer to the earth, and are thus seen as extended sources. If we consider a planet as a collection of a large number of pointsized sources of light, the total variation in the amount of light entering our eye from all the individual, point-sized sources will average out to zero, thereby nullifying the twinkling effect.
The biodegradable items are old clothes, wilted flowers, pencil shavings and vegetable peels.
The ‘Chipko Andolan’ ultimately benefit the local population in the following two ways:
(i) The Chipko movement quickly spread across communities and media, and forced the government, to whom the forests belongs, to rethink their priorities in the use of forest produce.
(ii) Participation of the local people lead to the efficient management of forests.
- Only half a water molecule is shown to be attached as water of crystallisation. It is written in this form because two formula units of CaSO4 share one molecule of water of crystallisation.
- Sodium hydrogencarbonate is an essential ingredient in antacids because being alkaline, it neutralises excess acid in the stomach and provides relief.
- When electricity is passed through an aqueous solution of sodium chloride, it decomposes to form sodium hydroxide, chlorine gas and hydrogen gas.
2NaCl (aq) + 2H2O (l) → 2NaOH (aq) + Cl2(g) + H2 (g)
The process is called the chlor-alkali process because of the products formed-chlor stands for chlorine and alkali for sodium hydroxide.
When dilute hydrochloric acid reacts with marble (calcium carbonate) then calcium chloride, carbon dioxide and water are formed.
When carbon dioxide gas is passed through lime water, the lime water turns milky due to the formation of a white precipitate of calcium carbonate.
- These oxides are called basic oxides and their solutions in water are called alkalis.
- This layer formed is protective oxide layer which prevents the metal from further oxidation.
- Some alkali can be cut with a knife because they are very soft and have low densities.
Carbon cannot form C4+ cation because removal of 4 electrons from a carbon atom would require a large amount of energy. Carbon cannot form C4- anion because it would be difficult for the nucleus with 6 protons to hold on to 10 electrons. Hence, carbon atoms share electrons forming covalent compounds. Covalent compounds do not form ions/charged particles and therefore do not conduct electricity.
Intermolecular forces of attraction are weak in covalent compounds, hence have low melting and boiling points.
- The given experimental set-up demonstrates that shoots respond by bending towards light (phototropism).
- Spinal cord (CNS)
- Effector = Muscle in the arm
- Suitable caption for the diagram is reflex arc or reflex action.
|S. No.||Movement in Sensitive Plant||Movement in Legs|
|1.||It occurs in response to an external stimulus like touch and shock.||It occurs in response to our requirement and is determined by will.|
|2.||Plant cells change shape by changing the amount of water (turgor changes).||Movement in our legs is voluntary action which is controlled by cerebellum in hind-brain.|
|3.||No nerves are involved.||Nerves carry the message for movement of legs.|
|4.||It is controlled by plant hormones.||It is controlled by nerves and cerebellum in hind-brain.|
- F1 progeny will have green coloured stem.
- 25% of purple-stemmed plants are obtained if F1 plants are self pollinated.
- In F2 progeny, ratio of GG will be 1 and that of Gg will be 2, i.e., GG: Gg = 1:2.
- The dwarf traits of the plants is not expressed in the presence of the dominant tall trait.
- In the F2 generation, both the tall and dwarf traits are present in the ratio of 3 : 1. This showed that the traits for tallness and dwarfness are present in the F1 generation, but the dwarfness, being the recessive trait does not express itself in the presence of tallness, the dominant trait.
- The statement made by the student is incorrect. Positions marked 3 (yellow) and 5 (blue) are similar to the core of a hard boiled egg and the colour of the sky respectively. The student is stating the nature of colours in reverse order.
- The position marked 7 (violet) corresponds closely to the colour of a solution of potassium permanganate.
- The position marked i (red) corresponds closely to the colour of ‘danger’ or stop signal lights.
A rainbow is a natural spectrum appearing in the sky after a rain. It is produced Sunlight by dispersion of sunlight by tiny water droplets, present in the atmosphere. The water droplets act like small prisms. When a ray of light falls on water drop (or raindrop) it undergoes refraction and dispersion to form a spectrum. This spectrum undergoes internal refraction (inside the raindrop) and finally refracted again when it comes out of the raindrop. After the dispersion of light and internal reflections, the band of colours reaches observer’s eye in the form of a rainbow.
A rainbow is always formed in the direction opposite to that of the sun.
Electromagnetic means having both electrical as well as magnetic character or properties. Induction means induced effect. Thus, the process by which a changing magnetic field in a conductor induces a current in another conductor, is called electromagnetic induction. The value of induced current produced in a circuit depends upon
- rate of change of magnetic flux.
- number of turns in the coil, and
- relative speed between the coil and the magnet.
The electric generator is a device based on electromagnetic induction.
A current carrying conductor has a magnetic field associated with it. The two magnetic fields, one due to the magnet and the other due to current in the conductor, interact. This produces a force on the conductor. The direction of force on the conductor depends on the strength of current and the strength of magnetic field. The direction of force is given by Fleming’s left-hand rule. According to this rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the first finger points in the direction of magnetic field and the second finger in the direction of current, then the thumb will point in the direction of motion or the force acting on the conductor.
- Shyam is concerned about the health of villagers as well as about ill-effects of industrial pollution on soil, water and air. Secondly, he shares his concerns with others and tries to convince them not to make such decision which will ultimately harm them.
- He explained to Ramu that if a brick factory is set up near the agricultural land, the smoke arising out of the burning of fossil fuel would harm the health of villagers. The acidic oxides in smoke would cause acid rain which would cause water and soil pollution affecting the agricultural produce.
- ‘X’is NaOH. When NaOH is treated with strong acid like HCl, neutralisation reaction occurs and salt is formed.
NaOH + HCl → NaCl + H2O
- No, ‘X’ cannot be stored in aluminium container because aluminium with a coating of oxide reacts with the NaOH to form
a salt and water.
- Distilled water does not conduct electricity because it does not contain any ionic compound like acids, bases or salts dissolved in it.
- When we overeat, excess of acid is produced in the stomach which causes burning sensation.
- Copper vessels tarnish due to formation of basic copper carbonate, which gets neutralised when rubbed with lemon which contains citric acid and the copper vessel regains its shine.
- Washing soda is sodium carbonate decahydrate which when exposed to air loses 10 molecules of water and changes to white powder.
- Sodium chloride is a salt of strong acid HCl and strong base NaOH, so it is a natual.
Sodium carbonate is a salt of weak acid H2CO3 and strong base NaOH, so it is basic.
- Noble gas – G
Halogen – F
- Most active metal – B
- Most electronegative in 3rd period – F
- Ionic bond
- Oxide formed by C would be basic.
- Xylem tissue might have blocked. Xylem is water conducting tissue of plants. Vessels and tracheids transport raw materials (water and minerals).
- The opening and closing of stomatal is influenced by movement of water into the guard cells. When water moves into guard cells, they swell and stretch causing stomatal pore to open. When water moves out of the guard cells, they shrink
and their inner walls come closer, stomatal pore closes.
- Testes produces sperms as well as secreates testosterone. Functions of testosterone are:
- Formation of sperms
- Development of secondary sexual characters
- Fallopian tubes/Oviduct
- Placenta, a special disc-like tissue embedded in the mother’s uterine wall and connected to the foetus or embryo. Placenta provides a large surface area for glucose and oxygen or nutrient to pass from the mother’s blood to the developing embryo or foetus.
- f =+ 15cm
Reason: Objects at S. No. (3) indicates u = – 30cm, v = +30cm
Thus, object is at 2F (2 f = 30 cm)
∴ f = 15 cm
- Observation at S. No. (6) is not correct. The value, u = -10 cm, indicates that the object is in between the optical centre and the focus (i.e., less than the focal length) of the lens and hence the image should be on the same side as the object. Thus, the image distance cannot be positive.
- u = – 20cm, u = + 60cm, f =+ 15 cm
1. A ray of light incident parallel to the principal axis after reflection passes through the principal focus.
A ray of light which passes through the centre of curvature after reflection retraces its path back.
Image of an object placed between pole and focus:
Distance between the object and the screen is |υ| – |u| = 60 – 20 = 40 cm.
- Both expressions P = 14 R and P orrect, but these are applicable in different situations. If current flowing in devices constant, then we apply the expression P=I2R. For example, when devices are connected in series, then current in devices is same and for comparison of powers consumed by different devices, we use the expression P = I2R.On the other hand, if voltage across a device is kept fixed; then we apply the expression, P = For example, when devices are connected in parallel (as in household circuit), then for calculating the power we use the expression P =
- The pure tungsten has high resistivity and a high melting point (nearly 3000°C), so when electric current passes through the filament then the electrical energy is converted to heat and light energy.
- Copper and aluminium have low values of resistivity, so copper and aluminium wires have low resistance; therefore, when current passes through them, the heat produced in these wires is negligible that is why electricity is transmitted with negligible power loss.
When ferrous sulphate crystals are heated, the colour changes from green to white because of dehydration and then a brown solid of ferric oxide is formed with the smell of burning sulphur.
The solution of the colour is green and that of the coating is reddish-brown. This is because iron being more reactive than Cu displaces Cu from CuSO4 and forms green coloured solution of FeSO4 and a reddish-brown layer of Cu gets deposited.
Opening of stomata is influenced more by blue light because oxygen concentration is maximum in blue light.
It is observed that the daughter cells of Amoeba and the bud of yeast are smaller in size than their respective parental cells.
- Convex lens.
- Real, inverted, enlarged. (Any two)
- When object is at 2F.
He will have to shift the mirror towards the screen. This is because the blurred image of an object is obtained only when the separation between the
screen and mirror is less than focal length.
According to Ohm’s law, the current through a conductor is directly proportional to the potential difference across its ends. Thus, the graph between I and V is a straight line passing through the origin.
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