CBSE Sample Papers for Class 10 Science Paper 6
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 6.
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.
The leaves of a plant first prepare food A by photosynthesis then food A gets converted into food B. What are A and B?
Question 2.
Name the parts of a bisexual flower that are not directly involved in reproduction.
Question 3.
Mention any two trends exhibited by elements when we go from left to right across the period of periodic table.
Question 4.
A pencil when dipped in water in a glass tumbler, appears to be bent at the interface of air and water. Will the pencil appear to be bent to the same extent, if instead of water we use liquids like, kerosene or turpentine. Support your answer with reason.
Question 5.
Although coal and petroleum are produced by degradation of bio-mass, yet we need to conserve them. Why? Mention two reasons.
Question 6.
Identify the substance oxidised, substance reduced, oxidising agent and reducing agent:
MnO2 + 4HCl — MnCl2 + 2H2O + Cl2
Question 7.
The colour of freshly prepared solution of copper sulphate gradually changes when an iron nail is dipped in it. Name the reaction that takes place and give a balanced chemical equation mentioning the state of the reactants and the products.
Question 8.
1. What are metalloids? Write any two examples.
2. Given below are some of the elements of first group
Li, Na, K
(Their atomic numbers are 3,11,19 respectively and they belong to 2nd, 3rd and 4″ period respectively.)
Arrange these in the decreasing order of metallic character exhibited by them.
OR
1. Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeléev.
2. Arrange the following elements in increasing order of their atomic radii:
- Li, Be, F, N
- Cl, At, Br, I
Question 9.
Om, Rohit and Kishore always remain in a hurry. One day, during lunch hour Om and Rohit started gulping food quickly. Kishore told them to eat slowly. But they didn’t listen to him and went out to play. Om suddenly developed stomach ache while playing. Answer the following questions based on the situation mentioned above.
- What according to you might have gone wrong with him?
- What advice would you give to him?
- What values are promoted by Kishore?
Question 10.
Mention one example each of viral and bacterial infections affecting the human reproductive system. What are such diseases called? How can they be prevented? Mention one more function of the above method used.
Question 11.
With the help of a cross done with garden pea plants, trace the work done by Mendel with a tall and a short plant to arrive at a 3:1 ratio in the F, generation.
Question 12.
Forelimbs of man and frog, are they homologous or analogous organs? Give reason for your choice. How does it help in the study of evolution?
OR
In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a better’ body design? Why or why not?
Question 13.
Size of image of an object formed by a mirror having a focal length of 20 cm, is observed to be reduced \(\frac { 1 }{ 3 }\) to rd of its size. At what distance the object has been placed from the mirror? What is the nature of the image and the mirror?
Question 14.
Compare the power used in the 2Ω resistor in each of the following circuit:
(i) a 6V battery in series with 1Ω and 2Ω resistors and
(ii) a 4V battery in parallel with 12Ω and 2Ω resistors.
OR
Two identical wires are first connected in series and then in parallel to a source of supply. Find the ratio of the heat produced in two cases.
Question 15.
Can a freely suspended current carrying solenoid stay in any direction? Justify your answer. What will happen when the direction of current in the solenoid is reversed? Explain.
Question 16.
Four metals A, B, C and D are in turn added to the following solutions one by one. The observation made are tabulated below:
Metal | Iron (II) Sulphate | Copper (II) Sulphate | Zinc Sulphate | Silver Sulphate |
A | No Reaction | Displacement | – | – |
B | Displacement | – | No Reaction | – |
C | No Reaction | No Reaction | No Reaction | Displacement |
D | No Reaction | No Reaction | No Reaction | No Reaction |
Answer the following questions based on the above information:
- Which is the most active metal and why?
- What would be observed if B is added to a solution of copper (II) sulphate and why?
- Arrange the metals A, B, C and D in order of increasing reactivity.
- Container of which metal can be used to store both zinc sulphate solution and silver nitrate solution?
- Which of the above solutions can be easily stored in a container made up of any of these metals?
Question 17.
- Draw the structures for the following compounds:
- 2-Bromopentane
- 2-methylpropane
- Butanal
- 1-Hexyne
- Draw the electron dot structure for ethanoic acid.
- Draw and explain the structure of the micelle. Which end of the micelle dissolves in dirt?
OR
- Write the name for the following compounds:
- Take about 3mL of Ethanol in a test tube and warm it gently in a water bath. Add a 5% solution of alkaline potassium permanganate drop by drop to the solution. What happens to the colour of KMnO4 added initially and then in excess? Give reason. Name the product of this reaction.
- What is scum?
Question 18.
- Name the two main organs of our central nervous system. Which one of the two plays a major role in sending command to muscles to act without involving thinking process? Name the phenomenon involved. Name the receptors which detect
- taste
- smell
- Draw a diagram of human brain and label on it cerebrum and cerebellum.
- State the role of cerebellum.
Question 19.
Study the diagram given below and answer the questions that follow:
- Which defect of vision is represented in this case? Give reason for your answer.
- What could be the two causes of this defect?
- With the help of a diagram show how this defect can be corrected using a suitable lens.
- The far point of a myopic person is 150 cm in front of eye. What is the nature and power of the lens required to correct this problem?
OR
- State the cause of dispersion, when white light enters a glass prism. Explain with a diagram.
- What is meant by least distance of distinct vision? How does this vary between the very young and old people?
Question 20.
In the arrangement shown in figure, there are two coils A and B wound on non-conducting cylindrical rod? Initially the key is not inserted. Then the key is inserted and later removed.
- State your observation in each case.
- State the conclusion based on your observations.
- Name the phenomenon and define it.
- Name the two coils.
Question 21.
-
- Mention any two advantages of constructing dams.
- Name a dam which was a subject of much opposition from locals as well as NGO’s.
- Mention any three problems which may arise due to construction of large dams.
- Name the group of chemical compound which adversely affects the ozone layer.
- Which of the following belonging to a food chain is likely to have maximum concentration of harmful chemicals in its body? Peacock, Frog, Snake, Grasshopper.
SECTION-B
Question 22.
Solid sodium bicarbonate was placed on a strip of pH paper. What was the change in colour?
Question 23.
List two observations which you make when you add a pinch of sodium hydrogen carbonate to acetic acid in a test tube. Write chemical equation for the reaction that occurs.
OR
Kanchi takes 5 mL of distilled water in four test tubes marked as A, B, C and D. She dissolves sodium chloride in test tube A, potassium chloride in test tube B, calcium chloride in test tube C and magnesium chloride in test tube D. In which test tubes will soap give good lather?
Question 24.
State two uses of filter paper while preparing a temporary mount of a leaf peel.
Question 25.
A student while studying the various parts of an embryo of a dicot seed made the following observations:
A. The embryo can be seen after separating the two cotyledons very carefully
B. Embryo is a tiny structure consisting of radicle and plumule.
C. The plumule consists of two very tiny leaves.
D. During germination plumule grows into root and radicle into stem.
- What is the wrong observation?
- Correct that statement.
Question 26.
In the given figure, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism it produces a spectrum XY on a screen.
- State the colour seen at X and Y.
- Why do different colours of white light bend through different angles with respect to the incident beam of light?
Question 27.
The following circuit diagram shows the experimental set-up for the study of dependence of current on potential difference. Which two circuit components are connected in series?
Answers
SECTION-A
Answers 1.
Food A → glucose, Food B → starch
Answers 2.
Parts of a bisexual flower not involved directly in reproduction are:
- Sepals or calyx
- Petals or Corolla
- Thalamus
Answers 3.
As we move from left to right in a periodic table:
- Atomic radius decreases
- Metallic character decreases
Answers 4.
No, bending will be different in different liquids since velocity of light at the interface separating two media depends on the relative refractive index of the medium. A substance having higher refractive index is optically denser than another substance having lower refractive index. Thus higher the refractive index of a substance, more it will change the direction of a beam of light passing through it.
Answers 5.
Both coal and petroleum take millions of years for their formation. As these resources are utilised at much faster rate than their formation, they will be exhausted in the near future. Hence they need to be conserved.
Answers 6.
Substance oxidised : HCl
Substance reduced : MnO,
Oxidising agent : MnO,
Reducing agent : HCI
Answers 7.
Displacement reaction takes place.
Answers 8.
- Metalloids : Elements exhibiting properties of both metals and non metals. E.g., silicon, germanium, boron, arsenic, etc.
- K > Na > Li
OR
- GeCl4, GaCl3
- F< N < Be < Li as the atomic radii decreases along a period.
- Cl < Br < I < At as the atomic radii increases down a group.
Answers 9.
- Om developed stomach ache as he had not chewed his food properly. Chewing food properly helps in proper breakdown of food and mixing it with saliva. Large food pieces if enter the stomach might cause damage.
- Chew your food properly for healthy digestion.
- Caring, health conscious and aware.
Answers 10.
Viral disease : Warts and AIDS
Bacterial disease : Gonorrhea and syphilis.
Such diseases are called Sexually Transmitted Diseases. They can be prevented by using a covering called condom for the penis. It can also be used to prevent pregnancies.
Answers 11.
Answers 12.Forelimbs of man and frog are homologous organs because the basic structure of the limbs are similar but they do different functions. It helps to identify evolutionary relationship between different species.
OR
There is no real ‘progress’ in the idea of evolution. Evolution is simply the generation of diversity by environmental selection. The only progressive trend in evolution seems to be that more and more complex body designs have emerged over time. However, again, it is not as if the older designs are inefficient. So many of the older and simpler designs still survive. In fact, one of the simplest life forms, i.e., bacteria inhabit the most inhospitable habitats like hot springs, deep-sea thermal vents and ice in Antarctica. In other words, human beings are not the pinnacle of evolution, but simply yet another species in the teeming spectrum of evolving life.
Answers 13.
An image smaller in size can be formed both by a concave mirror as well as a convex mirror.
Case I : When mirror is concave, the image is real.
Hence, m = \(-\frac { 1 }{ 3 }\), f = -20 cm
m = \(-\frac { \upsilon }{ u }\)
∴ \(-\frac { 1 }{ 3 }\) = \(-\frac { \upsilon }{ u }\)
Case II : When mirror is convex
Answers 14.
- When a 222 resistor is joined to a 6 V battery in series with 112 and 222 resistors, total resistance of the combination
Req = 2 + 1 + 2 = 5Ω
∴ Current in the circuit \(P_{ I }=\frac { 6V }{ 5\Omega } =1.2A\)
∴ Power used in the 282 resistor P = \({ I }_{ I }^{ 2 }\) IR =(1.2)2 × 2 = 2.88 W. - When 212 resistor is joined to a 4 V battery in parallel with 1212 and 212 resistors, current flowing in 212 resistor is independent of the other resistors.∴ Current flowing through 282 resistor \(I_{ 2 }=\frac { 4V }{ 2\Omega } =2A\)
∴ Power used in 212 resistor \({ P }_{ 2 }={ I }_{ 2 }^{ 2 }R=(2)^{ 2 }\times 2=8W\)
\(\frac { P_{ 1 } }{ P_{ 2 } } =\frac { 2.88W }{ 8W } =0.36:1\)
OR
Equivalent resistance in series
\(R_{ S }=R+R=2R\)
Rate of heat produced:
\({ P }_{ S }=\frac { V^{ 2 } }{ 2R }\)
Equivalent resistance in parallel
\(R_{ p }=\frac { R\times R }{ R+R } =\frac { R }{ 2 }\)
Rate of heat produced:
\({ P }_{ P }=\frac { V^{ 2 } }{ R/2 }\)
Answers 15.
No, a freely suspended current carrying solenoid will stay in north-south direction. We know that the direction of magnetic field is always perpendicular to the direction of current flow and the magnitude of the magnetic field inside a solenoid is directly proportional to the current flowing through the solenoid. Hence, when the direction of current in the solenoid is reversed, the direction of magnetic field is also reversed.
Answers 16.
- B, It is the only metal in the table which can displace iron from iron sulphate solution.
- It would displace copper from sulphate solution as metal B is higher in the reactivity series than copper.
- D < C < A < B
- D
- Zinc sulphate
Answers 17.
1.
2. Electron dot structure of ethanoic acid:
3. A soap molecule consists of two dissimilar parts:
- A short ionic part comprising the carboxylate salt, —COONa+. This is the polar end. This is water soluble (i.e., hydrophilic or water attracting) end, therefore, remains attached to water.
- A long hydrocarbon chain which is the non-polar end. This end is hydrophobic (i.e., water repelling) and is soluble in oil
and grease.
When soap is dissolved in water, it forms a colloidal suspension. In this colloidal suspension, the soap molecules cluster together to form micelles and remain radially suspended in water with the hydrocarbon end towards the centre and the ionic end directed outward. This is shown in the figure. The dirt particles always adhere to the oily or greasy layer present on the skin or clothes. When a dirty cloth is Dirt particles dipped into a soap solution, its non (oil or grease) polar hydrocarbon end of micelles attach to the grease or oil present in dirt and polar end remains in water Soap layer. The mechanical action of rubbing molecule mm Oils subsequently, dislodges the oily layer Water from the dirty surface shaping it into small globules. A stable emulsion of oil in water is formed. The emulsified oil or grease globules bearing the dirt can now be readily washed with water.
OR
-
- 2-methyl butane
- 2-Pentene
- Butanone
- 2-chlorobutane
- Colour of KMnO4 added initially disappeares due to oxidation of alcohol. When KMnO4 is added in excess it retains its colour. The product formed is ethanoic acid or acetic acid.
- Ca and Mg salts of soap is called scum.
Answer 18.
- The two main organs of our central nervous system are brain and spinal cord. Spinal cord plays a major role in sending command to muscles to act without involving thinking process. The phenomenon involved is reflex action.
- Gustatory receptor detects taste.
- Olfactory detects smell.
- (a)
- Cerebellum maintains the posture and equilibrium of the body.
Answer 19.
- Hypermetropia defect of vision is represented in this case. The defect is created when light rays from closeby objects are focused at a point behind the retina.
- Causes of the defect are:
- The focal length of the eye lens is too long.
- Eye ball becomes small.
- Nature of the lens is Concave.
Power, \(P=\frac { 1 }{ f }\)
= \(\frac { 1 }{ (-1.5) } D\)
= -0.6D
OR
1. Light is made of different colours. Each colour travels at its own speed and wavelength inside a prism. Therefore, they bend at different angles.
2. The minimum distance between the eye lens and the object to form a clear image is called least distance of distinct vision. At a young age it is less and at old age least distance of distinct vision is more.
Answer 20.
- Galvanometer shows a momentary deflection when key is inserted when key is removed again shows a momentary deflection but in opposite direction.
- Change in current through coil A changes magnetic field lines around the coil A as will around the coil B which causes an induced current in coil B and a deflection is produced in the galvanometer.
- Electromagnetic induction. Whenever there is a change in the magnetic field lines linked with a closed coil, a current is induced in it and it lasts as long as the change is taking place.
- A is called primary coil, B is called secondary coil.
Answer 21.
-
- Two advantages of constructing dams are irrigation and producing electricity.
- Sardar Sarovar Damo Narmada and Tehri Dam on Ganga
- Social problems, environmental problems and economic problems.
- Chlorofluorocarbons, ‘CFCs’
- Peacock, as it is at the top of the food chain.
Grass hopper → Frog → Snake → Peacock.
SECTION-B
Answer 22.
The colour of the pH paper did not change because pH paper shows colour depending on the hydrogen ion concentration in solution. Solid sodium bicarbonate does not produce hydrogen ions in its solid state thus does not give any colour on pH paper.
Answer 23.
Two observations made are:
- Brisk effervescence
- Evolution of a colour less and odour less gas.
CH3COOH + NaHCO3 – CH3COONa + H2O + CO2
OR
Soap will give good lather in test tubes A and B because magnesium chloride and calcium chloride make water hard and react with soap to form scum.
Answer 24.
- It is used to absorb the excess glycerine poured on the slide.
- It makes the mount clean, dry and tidy.
Answer 25.
- (D) is the wrong observation.
- Plumule grows into stem and radicle into root.
Answer 26.
- X — Violet
Y — Red - Different colours of white light bend through different angles with respect to the incident beam of light due to difference in speed of different wavelengths.
Answer 27.
Ammeter, cell and rheostat are connected in series. This is because only one common point exists between ammeter, cell and rheostat.
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