Brain Grain · braingrain.in
Science — Practice Paper · Set 1
Class: 7CBSE / NCERTMax Marks: 34
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 10 × 1 = 10
Choose the correct answer. (Answer all questions.)
1.Tick the correct answer: (a) In cockroaches, air enters the body through (i) lungs (ii) gills (iii) spiracles (iv) skin (b) During heavy exercise, we get cramps in the legs due to the accumulation of (i) carbon dioxide (ii) lactic acid (iii) alcohol (iv) water (c) Normal range of breathing rate per minute in an average adult person at rest is (i) 9-12 (ii) 15-18 (iii) 21-24 (iv) 30-33 (d) During exhalation, the ribs (i) move outwards (ii) move downwards (iii) move upwards (iv) do not move at alla. lungs / gills / spiracles / skinb. CO2 / lactic acid / alcohol / waterc. 9-12 / 15-18 / 21-24 / 30-33d. outwards / downwards / upwards / no movement[1]
2.One litre of water at 30 °C is mixed with one litre of water at 50 °C. The temperature of the mixture will be (a) 80 °C (b) more than 50 °C but less than 80 °C (c) 20 °C (d) between 30 °C and 50 °Ca. 80 °Cb. more than 50 °C but less than 80 °Cc. 20 °Cd. between 30 °C and 50 °C[1]
3.A wooden spoon is dipped in a cup of ice cream. Its other end (a) becomes cold by the process of conduction. (b) becomes cold by the process of convection. (c) becomes cold by the process of radiation. (d) does not become cold.a. becomes cold by the process of conductionb. becomes cold by the process of convectionc. becomes cold by the process of radiationd. does not become cold[1]
4.Choose the correct option from the following: Plants take carbon dioxide from the atmosphere mainly through their: (i) roots (ii) stem (iii) flowers (iv) leavesa. rootb. stemc. leafd. flower[1]
5.A virtual image larger than the object can be produced by a (i) concave lens (ii) concave mirror (iii) convex mirror (iv) plane mirrora. concave lensb. concave mirrorc. convex mirrord. plane mirror[1]
6.Choose the correct option from the following: Which part of the plant takes in carbon dioxide from the air for photosynthesis? (i) Root hair (ii) Stomata (iii) Leaf veins (iv) Sepalsa. Root hairb. Stomatac. Leaf veinsd. Sepals[1]
7.Tick the correct answer: (a) The reproductive part of a plant is the (i) leaf (ii) stem (iii) root (iv) flower (b) The process of fusion of the male and the female gametes is called (i) fertilisation (ii) pollination (iii) reproduction (iv) seed formation (c) Mature ovary forms the (i) seed (ii) stamen (iii) pistil (iv) fruit (d) A spore producing organism is (i) rose (ii) bread mould (iii) potato (iv) ginger (e) Bryophyllum can reproduce by its (i) stem (ii) leaves (iii) roots (iv) flowera. leaf / stem / root / flowerb. fertilisation / pollination / reproduction / seed formationc. seed / stamen / pistil / fruitd. rose / bread mould / potato / gingere. stem / leaves / roots / flower[1]
8.Which of the following statements is not correct? (i) Forests protect the soil. (ii) In forests, plants and animals depend on one another. (iii) Forests have no influence on climate. (iv) Soil helps forests to grow and regenerate.a. Forests protect the soil from erosion.b. Plants and animals in a forest are not dependent on one another.c. Forests influence climate, water cycle and air quality.d. Soil helps forests to grow and regenerate.[1]
9.The basic unit of speed is: (i) km/min (ii) m/min (iii) km/h (iv) m/sa. km/minb. m/minc. km/hd. m/s[1]
10.An electric iron of 1 kW is operated at 220 V. Which of the following fuses should be used in the circuit? (i) 1 A (ii) 3 A (iii) 5 A (iv) 13 Aa. 1 Ab. 3 Ac. 5 Ad. all of these[1]
Part II — Short Answer Questions 12 × 2 = 24
Answer briefly. (Answer all questions.)
11.Consider the following statements: (a) Both acids and bases change colour of all indicators. (b) If an indicator gives a colour change with an acid, it does not give a change with a base. (c) If an indicator changes colour with a base, it does not change colour with an acid. (d) Change of colour in an acid and a base depends on the type of the indicator. Which of these statements are correct? (i) All four (ii) a and d (iii) b and c (iv) only d[2]
12.Give two examples each of conductors and insulators of heat.[2]
13.Describe the process of neutralisation with the help of an example.[2]
14.Which type of lens forms always a virtual image?[2]
15.Why should we worry about the conditions and issues related to forests far from us?[2]
16.Write one similarity and one difference between the nutrition in Amoeba and human beings.[2]
17.The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also.[2]
18.Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?[2]
19.Find out the letters of English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.[2]
20.The rear view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be (i) 1 m/s (ii) 2 m/s (iii) 4 m/s (iv) 8 m/s[2]
21.Explain how painting of an iron gate prevents it from rusting.[2]
22.What are decomposers? Name any two of them. What do they do in the forest?[2]
🔑 Show Answer Key — Set 1
- 1. (a) (iii) spiracles (b) (ii) lactic acid (c) (ii) 15-18 (d) (ii) move downwards
- 2. (d) between 30 °C and 50 °C
- 3. (d) does not become cold.
- 4. (iv) leaves
- 5. (ii) concave mirror
- 6. (ii) Stomata
- 7. (a) (iv) flower (b) (i) fertilisation (c) (iv) fruit (d) (ii) bread mould (e) (ii) leaves
- 8. (iii) Forests have no influence on climate.
- 9. (iv) m/s
- 10. (iii) 5 A
- 11. (iv) only d
- 12. Conductors of heat: copper and aluminium. Insulators of heat: wood and plastic.
- 13. Neutralisation is the reaction between an acid and a base in which salt and water are formed and heat may be evolved. Example: hydrochloric acid reacts with sodium hydroxide to form sodium chloride and water.
- 14. A concave lens always forms a virtual image.
- 15. Forests affect the whole environment by maintaining oxygen and carbon dioxide balance, rainfall, climate, soil and water resources. Loss or damage to distant forests can therefore affect air, water cycle, biodiversity and human life everywhere.
- 16. Similarity: both Amoeba and humans ingest, digest, absorb, assimilate and egest food. Difference: Amoeba engulfs food with pseudopodia and digests it in a food vacuole, while humans take food through the mouth and digest it in a well-developed digestive canal.
- 17. The car travels 15.0 km. Its speed is 0.75 km/min, or 45 km/h.
- 18. Dorji can test each drink with indicators such as litmus. The drink that turns blue litmus red is acidic. The drink that turns red litmus blue is basic. The drink that does not change either red or blue litmus is neutral.
- 19. Letters with vertical symmetry look the same in a plane mirror. In block capital English letters, examples include A, H, I, M, O, T, U, V, W, X and Y, depending on the font.
- 20. (iii) 4 m/s
- 21. Rusting needs oxygen and water. Paint forms a protective layer on the iron surface and prevents air and moisture from coming in contact with iron, so rusting is slowed or prevented.
- 22. Decomposers are organisms that break down dead plants, dead animals and wastes into simpler substances. Bacteria and fungi are decomposers. In forests they convert dead matter into humus and recycle nutrients into the soil.
Brain Grain · braingrain.in
Science — Practice Paper · Set 2
Class: 7CBSE / NCERTMax Marks: 34
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 10 × 1 = 10
Choose the correct answer. (Answer all questions.)
1.Stainless steel pans are usually provided with copper bottoms. The reason for this could be that (a) copper bottom makes the pan more durable. (b) such pans appear colourful. (c) copper is a better conductor of heat than the stainless steel. (d) copper is easier to clean than the stainless steel.a. copper bottom makes the pan more durableb. such pans appear colourfulc. copper is a better conductor of heat than the stainless steeld. copper is easier to clean than the stainless steel[1]
2.Choose the correct option: (a) In plants, water is transported through (i) xylem (ii) phloem (iii) stomata (iv) root hair (b) Water absorption through roots can be increased by keeping the plants (i) in the shade (ii) in dim light (iii) under the fan (iv) covered with a polythene baga. xylem / phloem / stomata / root hairb. shade / dim light / under the fan / covered with polythene bag[1]
3.An iron ball at 40 °C is dropped in a mug containing water at 40 °C. The heat will (a) flow from iron ball to water. (b) not flow from iron ball to water or from water to iron ball. (c) flow from water to iron ball. (d) increase the temperature of both.a. flow from iron ball to waterb. not flow from iron ball to water or from water to iron ballc. flow from water to iron balld. increase the temperature of both[1]
4.Tick the correct answer: (a) Cuscuta is an example of: (i) autotroph (ii) parasite (iii) saprotroph (iv) host (b) The plant which traps and feeds on insects is: (i) Cuscuta (ii) china rose (iii) pitcher plant (iv) rosea. autotroph / parasite / saprotroph / hostb. Cuscuta / china rose / pitcher plant / rose[1]
5.Which of the following is not a forest product? (i) Gum (ii) Plywood (iii) Sealing wax (iv) Kerosenea. gumb. plywoodc. sealing waxd. kerosene[1]
6.Which of the following relations is correct? (i) Speed = Distance × Time (ii) Speed = Distance/Time (iii) Speed = Time/Distance (iv) Speed = 1/Distance × Timea. speed = distance × timeb. speed = distance / timec. speed = time / distanced. speed = 1 / distance × time[1]
7.Tick the correct answer: (a) In cockroaches, air enters the body through (i) lungs (ii) gills (iii) spiracles (iv) skin (b) During heavy exercise, we get cramps in the legs due to the accumulation of (i) carbon dioxide (ii) lactic acid (iii) alcohol (iv) water (c) Normal range of breathing rate per minute in an average adult person at rest is (i) 9-12 (ii) 15-18 (iii) 21-24 (iv) 30-33 (d) During exhalation, the ribs (i) move outwards (ii) move downwards (iii) move upwards (iv) do not move at alla. lungs / gills / spiracles / skinb. CO2 / lactic acid / alcohol / waterc. 9-12 / 15-18 / 21-24 / 30-33d. outwards / downwards / upwards / no movement[1]
8.One litre of water at 30 °C is mixed with one litre of water at 50 °C. The temperature of the mixture will be (a) 80 °C (b) more than 50 °C but less than 80 °C (c) 20 °C (d) between 30 °C and 50 °Ca. 80 °Cb. more than 50 °C but less than 80 °Cc. 20 °Cd. between 30 °C and 50 °C[1]
9.A wooden spoon is dipped in a cup of ice cream. Its other end (a) becomes cold by the process of conduction. (b) becomes cold by the process of convection. (c) becomes cold by the process of radiation. (d) does not become cold.a. becomes cold by the process of conductionb. becomes cold by the process of convectionc. becomes cold by the process of radiationd. does not become cold[1]
10.Choose the correct option from the following: Plants take carbon dioxide from the atmosphere mainly through their: (i) roots (ii) stem (iii) flowers (iv) leavesa. rootb. stemc. leafd. flower[1]
Part II — Short Answer Questions 12 × 2 = 24
Answer briefly. (Answer all questions.)
11.Name the source from which litmus solution is obtained. What is the use of this solution?[2]
12.Describe how crystals of copper sulphate are prepared.[2]
13.When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.[2]
14.Can we survive only on raw, leafy vegetables/grass? Discuss.[2]
15.Describe the steps involved in getting clarified water from wastewater.[2]
16.Why do we often sneeze when we inhale a lot of dust-laden air?[2]
17.Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.[2]
18.Explain why rusting of iron objects is faster in coastal areas than in deserts.[2]
19.State the characteristics of the image formed by a plane mirror.[2]
20.Explain why: (a) An antacid tablet is taken when you suffer from acidity. (b) Calamine solution is applied on the skin when an ant bites. (c) Factory waste is neutralised before disposing it into the water bodies.[2]
21.Where is the bile produced? Which component of the food does it help to digest?[2]
22.Give a brief description of the process of synthesis of food in green plants.[2]
🔑 Show Answer Key — Set 2
- 1. (c) copper is a better conductor of heat than the stainless steel.
- 2. (a) (i) xylem (b) (iii) under the fan
- 3. (b) not flow from iron ball to water or from water to iron ball.
- 4. (a) (ii) parasite (b) (iii) pitcher plant
- 5. (iv) Kerosene
- 6. (ii) Speed = Distance/Time
- 7. (a) (iii) spiracles (b) (ii) lactic acid (c) (ii) 15-18 (d) (ii) move downwards
- 8. (d) between 30 °C and 50 °C
- 9. (d) does not become cold.
- 10. (iv) leaves
- 11. Litmus solution is obtained from lichens. It is used as an indicator to test whether a substance is acidic or basic.
- 12. Take water in a beaker, add a few drops of dilute sulphuric acid and heat it. Dissolve copper sulphate powder in the hot water until no more dissolves. Filter the solution and allow it to cool undisturbed. Blue crystals of copper sulphate form on cooling.
- 13. A current-carrying wire behaves like a magnet and produces a magnetic field around it. This magnetic field affects the compass needle, so the needle is deflected from its north-south position.
- 14. No. Raw leafy vegetables provide vitamins, minerals and fibre, but they do not by themselves supply all nutrients in required amounts. Humans also cannot digest cellulose efficiently like ruminants. A balanced diet containing carbohydrates, proteins, fats, vitamins, minerals and water is needed for healthy survival.
- 15. Wastewater first passes through bar screens that remove large objects. It then goes to a grit and sand removal tank where sand and grit settle. In a large settling tank, solids settle as sludge and oils or grease are skimmed off. Air is then passed through the clarified water to help aerobic bacteria grow and consume organic waste. The water is finally disinfected before it is released or reused.
- 16. Dust particles irritate the lining of the nasal cavity. Sneezing is a reflex action that forcefully expels air and helps remove these unwanted particles from the nose.
- 17. The solution may be basic or neutral. Blue litmus turns red only in an acidic solution; it remains blue in both basic and neutral solutions. To confirm, red litmus should also be tested: a base turns it blue, while a neutral solution does not change it.
- 18. Coastal air contains more moisture and salts, and rusting requires moisture and oxygen. Desert air is much drier, so iron objects rust more slowly there than in coastal areas.
- 19. The image formed by a plane mirror is virtual, erect, of the same size as the object, laterally inverted and appears as far behind the mirror as the object is in front of it.
- 20. (a) An antacid is basic, so it neutralises excess acid in the stomach. (b) An ant sting injects formic acid; basic calamine solution neutralises it and gives relief. (c) Factory wastes may be acidic or basic and can harm aquatic life, so they are neutralised before disposal.
- 21. Bile is produced by the liver and stored temporarily in the gall bladder. It helps in the digestion of fats.
- 22. Green plants make food by photosynthesis. Leaves take carbon dioxide from air through stomata and water is brought from the soil by roots. Chlorophyll in the leaves captures sunlight and uses its energy to make carbohydrates. Oxygen is released during the process.
Brain Grain · braingrain.in
Science — Practice Paper · Set 3
Class: 7CBSE / NCERTMax Marks: 34
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 10 × 1 = 10
Choose the correct answer. (Answer all questions.)
1.A virtual image larger than the object can be produced by a (i) concave lens (ii) concave mirror (iii) convex mirror (iv) plane mirrora. concave lensb. concave mirrorc. convex mirrord. plane mirror[1]
2.Choose the correct option from the following: Which part of the plant takes in carbon dioxide from the air for photosynthesis? (i) Root hair (ii) Stomata (iii) Leaf veins (iv) Sepalsa. Root hairb. Stomatac. Leaf veinsd. Sepals[1]
3.Tick the correct answer: (a) The reproductive part of a plant is the (i) leaf (ii) stem (iii) root (iv) flower (b) The process of fusion of the male and the female gametes is called (i) fertilisation (ii) pollination (iii) reproduction (iv) seed formation (c) Mature ovary forms the (i) seed (ii) stamen (iii) pistil (iv) fruit (d) A spore producing organism is (i) rose (ii) bread mould (iii) potato (iv) ginger (e) Bryophyllum can reproduce by its (i) stem (ii) leaves (iii) roots (iv) flowera. leaf / stem / root / flowerb. fertilisation / pollination / reproduction / seed formationc. seed / stamen / pistil / fruitd. rose / bread mould / potato / gingere. stem / leaves / roots / flower[1]
4.Which of the following statements is not correct? (i) Forests protect the soil. (ii) In forests, plants and animals depend on one another. (iii) Forests have no influence on climate. (iv) Soil helps forests to grow and regenerate.a. Forests protect the soil from erosion.b. Plants and animals in a forest are not dependent on one another.c. Forests influence climate, water cycle and air quality.d. Soil helps forests to grow and regenerate.[1]
5.The basic unit of speed is: (i) km/min (ii) m/min (iii) km/h (iv) m/sa. km/minb. m/minc. km/hd. m/s[1]
6.An electric iron of 1 kW is operated at 220 V. Which of the following fuses should be used in the circuit? (i) 1 A (ii) 3 A (iii) 5 A (iv) 13 Aa. 1 Ab. 3 Ac. 5 Ad. all of these[1]
7.Stainless steel pans are usually provided with copper bottoms. The reason for this could be that (a) copper bottom makes the pan more durable. (b) such pans appear colourful. (c) copper is a better conductor of heat than the stainless steel. (d) copper is easier to clean than the stainless steel.a. copper bottom makes the pan more durableb. such pans appear colourfulc. copper is a better conductor of heat than the stainless steeld. copper is easier to clean than the stainless steel[1]
8.Choose the correct option: (a) In plants, water is transported through (i) xylem (ii) phloem (iii) stomata (iv) root hair (b) Water absorption through roots can be increased by keeping the plants (i) in the shade (ii) in dim light (iii) under the fan (iv) covered with a polythene baga. xylem / phloem / stomata / root hairb. shade / dim light / under the fan / covered with polythene bag[1]
9.An iron ball at 40 °C is dropped in a mug containing water at 40 °C. The heat will (a) flow from iron ball to water. (b) not flow from iron ball to water or from water to iron ball. (c) flow from water to iron ball. (d) increase the temperature of both.a. flow from iron ball to waterb. not flow from iron ball to water or from water to iron ballc. flow from water to iron balld. increase the temperature of both[1]
10.Tick the correct answer: (a) Cuscuta is an example of: (i) autotroph (ii) parasite (iii) saprotroph (iv) host (b) The plant which traps and feeds on insects is: (i) Cuscuta (ii) china rose (iii) pitcher plant (iv) rosea. autotroph / parasite / saprotroph / hostb. Cuscuta / china rose / pitcher plant / rose[1]
Part II — Short Answer Questions 12 × 2 = 24
Answer briefly. (Answer all questions.)
11.Match structures given in Column I with functions given in Column II: Column I: Stomata, Xylem, Root hairs, Phloem. Column II: Absorption of water, Transpiration, Transport of food, Transport of water.[2]
12.Look at Fig. 3.13. Mark where the heat is being transferred by conduction, by convection and by radiation. The figure shows water boiling in a metal pan kept on a burner flame, with a metal handle attached to the pan.[2]
13.Show the shape of the distance-time graph for the motion in the following cases: (i) A car moving with a constant speed. (ii) A car parked on a side road.[2]
14.What makes the blood look red?[2]
15.What are the components of blood?[2]
16.Does transpiration serve any useful function in the plants? Explain.[2]
17.Which of the following are not correct? (i) The basic unit of time is second. (ii) Every object moves with a constant speed. (iii) Distances between two cities are measured in kilometres. (iv) The time period of a given pendulum is not constant. (v) The speed of a train is expressed in m/h.[2]
18.Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere.[2]
19.What is a virtual image? Give one situation where a virtual image is formed.[2]
20.Mark 'T' if the statement is true and 'F' if it is false: (a) We can obtain an enlarged and erect image by a convex mirror. (T/F) (b) A concave lens always form a virtual image. (T/F) (c) We can obtain a real, enlarged and inverted image by a concave mirror. (T/F) (d) A real image cannot be obtained on a screen. (T/F) (e) A concave mirror always form a real image. (T/F)[2]
21.Describe the different methods of asexual reproduction. Give examples.[2]
22.Fill in the blanks: (a) Cleaning of water is a process of removing __________. (b) Wastewater released by houses is called __________. (c) Dried __________ is used as manure. (d) Drains get blocked by __________ and __________.[2]
🔑 Show Answer Key — Set 3
- 1. (ii) concave mirror
- 2. (ii) Stomata
- 3. (a) (iv) flower (b) (i) fertilisation (c) (iv) fruit (d) (ii) bread mould (e) (ii) leaves
- 4. (iii) Forests have no influence on climate.
- 5. (iv) m/s
- 6. (iii) 5 A
- 7. (c) copper is a better conductor of heat than the stainless steel.
- 8. (a) (i) xylem (b) (iii) under the fan
- 9. (b) not flow from iron ball to water or from water to iron ball.
- 10. (a) (ii) parasite (b) (iii) pitcher plant
- 11. Stomata - Transpiration; Xylem - Transport of water; Root hairs - Absorption of water; Phloem - Transport of food.
- 12. Mark conduction in the metal pan and along its metal handle. Mark convection in the water inside the pan, where hot water rises and cooler water sinks. Mark radiation from the burner flame to the pan and to nearby surroundings.
- 13. (i) For a car moving with constant speed, the distance-time graph is a straight sloping line. (ii) For a parked car, the graph is a horizontal straight line because distance from the starting point does not change with time.
- 14. Blood looks red because red blood cells contain the red pigment haemoglobin.
- 15. Blood is made of plasma, red blood cells, white blood cells and platelets.
- 16. Yes. Transpiration creates a suction pull that helps draw water and minerals upward from roots to leaves. It also helps cool the plant.
- 17. Statements (ii), (iv) and (v) are not correct.
- 18. Green plants in forests take in carbon dioxide and release oxygen during photosynthesis. Animals and plants use oxygen for respiration and release carbon dioxide. Forests therefore help maintain the balance of oxygen and carbon dioxide in the atmosphere.
- 19. A virtual image is an image that cannot be obtained on a screen. A plane mirror forms a virtual image of an object placed in front of it.
- 20. (a) F (b) T (c) T (d) F (e) F
- 21. Asexual reproduction takes place without seeds and from a single parent. In vegetative propagation, new plants grow from roots, stems or leaves, for example potato from eyes and Bryophyllum from leaves. In budding, a small bud grows on the parent and separates, as in yeast. In fragmentation, the body breaks into pieces and each piece grows into a new organism, as in Spirogyra. In spore formation, spores germinate into new individuals, as in fungi such as bread mould.
- 22. (a) pollutants (b) sewage (c) sludge (d) oils and fats