The question paper comprises of two sections, A and B. You are to attempt both the sections. i) All questions are compulsory. ii) There is no overall choice. However, internal choice has been provided in all the five questions of five marks category. Only one option in such questions is to be attempted. iii) All questions of Section A and all questions of Section B are to be attempted separately. iv) Question numbers 1 to 3 in Section A are one-mark questions. These are to be answered in one word or one sentence.
v) Question numbers 4 to 7 in Section A are two-mark questions. These are to be answered in about 30 words each. vi) Question numbers 8 to 19 in Section A are three-mark questions. These are to be answered in about 50 words each. vii) Question numbers 20 to 24 in Section A are five-mark questions. These are to be answered in about 70 words each. viii)Question numbers 25 to 42 in Section B are multiple choice questions based on practical skills. Each question is a one-mark question. You are to select the most appropriate response out of the four provided to you.
Questions Section A Q 1: What is diffusion? Q 2: Identify the tissue:i) in aquatic plants that gives them buoyancy to float. ii) that contains chlorophyll. Q 3: What is thrust? Q 4: Why does lemonade become cool when ice cubes are added to it? Q 5: What is centripetal force? Give one example of an object moving due to this force. Q 6: Write any four functions of vacuoles. Q 7: Why is a neuron long and branched?
Q 8: i) Explain: Our body has a special mechanism to cool down during summers. ii) Give one example of each to prove that solids, liquids and gases can diffuse into liquids. Q 9: i) What is the principle used in centrifugation? ii) Write any two applications of centrifugation and chromatography.
Q 10: A car goes from A to B with a speed of 60 km/h and returns back with a speed of 80 km/h. Calculate the average velocity of the car. Q 11: i) What is the direction and name of the force which always opposes motion? ii) A force produces an acceleration of 3m/s 2 in body A and 4 m/s 2 in another body B. Find the ratio of masses. Q 12: Show how the gravitational force between two objects will change if the i) distance between them is tripled. ii) mass of both the objects is doubled.
Q 13: Study the distance time graph shown here:-
i) What does this graph tell you about the motion of the object? ii) Find the speed of the object from this graph.
Q 14: A ball thrown vertically upwards attains a maximum height of 19.6 m and then falls down. a) Find the initial velocity of the ball. a) Time taken by the ball to reach the highest point. b) Velocity of the ball one second before it reaches the maximum height
Q 15: It rains very little in many parts of India. Such regions have to face drought like situation every year. Ramu, a farmer from one such village gathers all the villagers and presents a proposal to dig a common tank to collect rainwater so that it can be used for irrigation and drinking purposes throughout the year. i) What are tanks? ii) In order to dig a tank, what values should the farmers have? iii) Can you suggest some modern methods of irrigation that can avoid wastage of water?
Q 16: Draw a well labelled diagram of the tissue of involuntary muscles found in the 1) heart 2) alimentary canal
Q 17: Explain the internal structure of plastids. Write about the types of plastids and their functions. Q 18: Write the three ways by which the insect pests attack the plants. How are they controlled?
Q 19: Where do we find areolar tissue in our body? What is its function?
Q 20: i) Draw suitable diagrams to show interparticle spaces in the three states of matter. ii) Arrange the three states of matter in ascending order of the force of attraction between their particles. iii) Explain with the help of an activity that particles of matter are continuously moving. OR Q 20: i) Will the temperature of water increase 10 seconds after it has reached its boiling point when heat is supplied to it? If yes, why? If no, why? ii) Clothes do not dry quickly during rainy season. Give reason iii) We use a hot iron to dry damp clothes in rainy season or spread them under a fan. Explain why?
Q 21: i) What are metalloids? Give two examples ii) Write the difference between a colloid and a suspension. Give 2 examples of each OR Q 21: i) Explain: Air is a solution. ii) You are given a mixture of cooking oil and water. Explain how you will separate them. Q 22: i) State Newtons first law of motion. ii) Why is it advisable to wear seat belts while driving? iii) How can we state first law of motion from the mathematical expression for the 2nd law of motion? OR Q 22: i) Why is it advisable to tie any luggage kept on the roof of a bus? ii) A bullet of 10 g moving with a velocity 50 m/s hits a wooden plank of mass 60g which is at rest. But when the bullet hits the plank, it remains in the plank and both move with a certain velocity. Find their velocity.
Q 23: i) What is acceleration? Give its formula. ii) A train moves with a constant acceleration. Its speed increases from 72 km/h to 180 km/h in 20 sec. Find the acceleration of the train in m/s2 and distance traveled by it in km. OR Q 23:
i) Observe the velocity time graph of two objects A and B. ii) Find the acceleration of object B. iii) Find the distance travelled by object A and object B.
Q 24: i) What is mixed farming? ii) Name the Italian variety of bee commonly used for honey production. Give reasons why this bee is used. iii) What are factors on which quality and taste of honey depends? OR
Q 24: i) What do you understand about the internal and external parasites on cattle? ii) Name any two internal parasites and the organs of the cattle they affect. iii) What are the two qualities desirable in cattle? iv) Give one example each of a local breed and exotic breed of cattle. Section B
Q 25: Starch is a type of 1) Carbohydrate 1) Protein 2) Vitamin 3) Mineral
Q 26: Which one of the following statements is true about conc HCL? 1) It is a weak acid 2) It is a harmless acid 3) It is a corrosive acid 4) It is immiscible in water
Q 27: The mixture of egg albumin and water is a ________ 1) solution 2) colloid 3) suspension 4) neither a colloid nor a suspension
Q 28: You are given four samples in four different containers as follows A – Milk B – Sandy water C – Sugar solution D – Chalk powder in water Which of these will be stable? 1) Milk and sandy water. 2) Sandy water and sugar solution.
3) Sandy water and chalk powder in water. 4) Milk and sugar solution. Q 29: Four students A, B, C, D have written the observations, after heating copper sulphate crystals. Which students have written incorrect observations? Student A – The blue colour of copper sulphate crystals turns white on heating Student B – The green colour of copper sulphate crystals turns blue on heating Student C – Water droplets can be seen on the upper-inner side of the test tube while heating the crystals. Student D – Sulphur dioxide gas is released on heating. 1) 2) 3) 4) A and B B and C A and C B and D
Q 30: Carbon disulphide is added to a mixture of sulphur and iron and also to a compound of iron and sulphur in test tubes A and B respectively.
What do we observe in the test tubes? A – No change. A – Sulphur dissolves and iron particles settle down. A – Iron dissolves and sulphur remains at the bottom. A – Both iron and sulphur dissolve. Q 31: Fe(s) + S(s) FeS Here, FeS is a _________ 1) Compound 2) Mixture 3) Element 4) Colloid B – The compound dissolves. B – Nothing dissolves. B – Gas is evolved. B – Iron separates from sulphur.
Q 32: A physical change takes place in which of the following?
Q 33: Which of these can we use to scrape cheek cells? 1) A needle 2) A knife 3) A toothpick 4) A glass slide
Q 34: Onion cells have a large central ________ 1) nucleus 2) vacuole 3) chloroplast 4) cytoplasm
Q 35: Which of these processes is responsible for swelling up of raisins kept in water? 1) Biogenesis 2) Plasmolysis 3) Endocytasis 4) Osmosis
Q 36: What is the boiling point of distilled water under atmospheric pressure? 1) 98 o C 2) 100o C 3) 101.1o C 4) 98.6 o C
Q 37: What should be position of the thermometer in experiment A and in experiment B.
1) A – Completely dipped in water. B – Completely dipped in ice. 2) A – 2-3 cm above the surface of water. B – Slightly dipped in the ice pieces. 3) A – Slightly dipped in the water. B – 2-3 cm above the pieces of ice. 4) A – 2-3 cm above the surface of water. B – Just touching the surface of ice pieces.
Q 38: The process of composting can be hastened by using 1) Hookworms 2) Rodents 3) Earthworms 4) Tapeworms Q 39: Which of these is a simple permanent tissue? 1) Xylem 2) Parenchyma 3) Phloem 4) Meristematic tissue Q 40:
Which one of the figures show cardiac muscles? 1) A 2) B 3) C 4) D
Q 41: Which of these students have arranged the spring balance in a correct way?
1) 2) 3) 4)
Student A Student B Student C Student D
Q 42: What would be the net force on the block?
1) (F1 + F2) – F3 2) (F1 – F2) + F3 3) (F1 × F2) + F3 4) (F1 – F2) – F3
Answers A1: Diffusion is the inter mixing of particles of two different types of matter on their own.
A 2: i) Aerenchyma. ii) Chlorenchyma. A 3: Thrust is the force acting on an object perpendicular to its surface. A 4: The temperature of water is more than ice. When ice cubes are added to lemonade, the ice cubes gain heat energy from the water in lemonade and melt. Thus, the lemonade becomes cool as it loses heat energy. A 5: Centripetal force is the force that acts on a body moving along a circular path and acts towards the centre of the moving body.
For example : – The motion of the moon around the earth is due to centripetal force. A 6: Functions of vacuoles In plants, vacuoles are full of cell sap. They provide turgidity and rigidity to the cell. Many important substances like amino acids, sugars, various organic acids and some proteins are stored in the vacuoles of plant cells. In amoeba, the food vacuole contains the food items consumed by it. In some unicellular organisms, vacuoles play an important role in expelling excess water and some wastes from the cell.
A 7: The size and shape of a cell depends upon its function. The function of a neuron is to carry messages quickly over a long distance. The branched structure helps the neuron to collect information from the various parts of the body and also to connect to another neuron. In this way, the message can be carried quickly and reliably over a long distance.
A 8: i) During summer we perspire. The particles of the liquid (sweat) gain energy from the surroundings or body surface and change into vapour. The heat energy equal to the latent heat of vaporisation is absorbed from the body. This cools the body. Thus, perspiration is a form of cooling mechanism. ii) Examples:- Solid into liquid – Salt into water. Liquid into liquid – Blue ink into water. Gas into liquid – Oxygen into water.
A 9: i) Principle used in centrifugation:- When a mixture is spun rapidly, the lighter particles stay at the top while the denser particles remain at the bottom. ii) Applications of centrifugation Used in dairies and home to separate butter from cream. Used in washing machines to squeeze out water from wet clothes. Used in diagnostic laboratories for blood and urine tests. (Write any two) Applications of chromatography To separate drugs from blood. To separate colours in a dye. To separate pigments from natural colours. (Write any two)
A 10: Let the distance between A to B = (d) km Time taken to go from A to B = (t1 ) h Time taken to return back from B to A = (t2 ) h When the car goes from A to B 60 = d t1 or d = 60 t1 — (1) And when the car returns back from B to A 80 = d t2 or d = 80 t2 — (2) From (1) and (2), we get 60 t1 = 80 t2 t1 = 80 t2 = 4 t2 — (3) 60 3 Average velocity = Total distance travelled Total time taken =2d t 1 + t2 = 2 (80 t2) 4 t 2 + t2 3 = 160 t2 × 3 7 t2 = 480 7 = 68.57 km/h Hence, average velocity of the car = 68.57 km/h.
A 11: i) Frictional force acts in the direction opposite to the direction of motion and always opposes motion. ii) Let the force acting on both the bodies be F. Let the mass of body A be m 1 and of body B be m 2 Using F = ma, we get F = m1 × 3 —(1) F = m2 × 4 —(2) From (1) and (2), m1 × 3 = m2 × 4
The ratio of the masses = 4:3
A 12: We know that gravitational force between two objects
i) If the distance between them is tripled, then
Thus, if the distance between the two objects is tripled, the gravitation force between them will become 1 th the original force. 9 ii) If mass of both the objects is doubled:
Thus, if the mass of both the objects is doubled, the gravitational force will become 4 times the original force.
A 13: (i) The motion of the object is uniformly accelerated. (ii)
To find the speed of the object, we plot two points A1 and A2 on the graph. Speed of the object = s2 – s1 t 2 – t1 = (60 – 20)m (45 – 15)s = 40 30 = 1.33 m/s
A 14: Given:- Maximum height (h) = 19.6 m Final velocity of the ball (v) = 0 (a) Using v2 – u2 = 2gh, we get 0 – u2 = 2 × (– 9.8) × 19.6 – u2 = – (19.6 × 19.6) u = 19.6 m/s Thus, initial velocity of the ball = 19.6 m/s (b) We know that, g=v–u t – 9.8 × t = 0 – 19.6
Time taken by the ball to reach the highest point = 2 s (c) Velocity of the ball in the 1st second (v) i.e. when t = 1 is: v=u+gt v = 19.6 + (– 9.8) × 1 = 19.6 – 9.8 v = 9.8 m/s Thus, velocity of the ball one second before it reaches the maximum height = 9.8 m/s
A 15: i) Tanks are small storage reservoirs which intercept and store the run off of smaller catchment areas. ii) All the farmers should have the values like team work, co-operation and determination to achieve the task. iii) Some modern methods of irrigation that can save water are a. Sprinkler system b. Drip irrigation
A 17: The internal structure of plastids consists of numerous membrane layers embedded in a material called the stroma.Their external structure is similar to mitochondria. They have their own DNA and ribosomes. Plastids are of two types i) Chromoplasts and ii) Leucoplasts Chromoplasts are coloured plastids. In chromoplasts, the plastids containing chlorophyll are called chloroplasts. They play an important role in photosynthesis. Leucoplasts are white or colourless plastids. They store materials like starch, oils and proteins granules.
A 18: The three ways by which insect pests attack the plants are:a. they cut the root, stem and leaf b. they suck the cell sap from the various parts of the plant c. they bore into stem and fruits Insect pests are controlled by spraying chemicals like insecticides and pesticides on crops or by treating the seeds and soil with these chemicals. A 19: Areolar connective tissue is found: a) between the skin and muscles b) around blood vessels and nerves c) in the bone marrow Functions of areolar connective tissue i) It fills the space between the internal organs ii) It supports the internal organs iii) It helps in repair of tissue.
A 20: i)
ii) The ascending order is as follows Gas < Liquid < Solid iii) To understand that particles of matter are continuously moving, take a lit incense stick. Place it at one of the corners of the room. After sometime, the smell of incense stick spreads into the entire room. This happens because, the particles in the smoke (gas) formed by burning of the incense stick are continuously moving. They mix with the particles of air and so we can get the smell of the incense stick from a distance. OR A 20: i) No, the temperature of water will not increase after it has reached its boiling point even though heat is supplied to it. This is because the heat gets used up in changing the state of water from liquid to vapour by overcoming the forces of attraction between the particles. So the supplied heat energy is absorbed by the water without showing any rise in the temperature.
ii) During rainy season, the amount of water vapour is more in the atmosphere. The air around us cannot hold more than a definite amount of water vapour at a given temperature. So, the rate of evaporation is less in rainy season and the clothes do not dry quickly during this season. iii) We use a hot iron to dry damp clothes because the rate of evaporation increases ith increase in temperature.
This helps to dry the damp clothes. Also, when we spread the clothes near a fan, the rate of evaporation increases due to increase in wind speed. A 21: Some elements which have intermediate properties between those of metal and nonmetals are called metalloids. Examples- Boron, Silicon, Germanium etc. Colloid The particles of colloid cannot be seen by naked eyes. A colloid is stable. For example:-Milk, smoke, cheese. Suspension The particles of suspension can be seen by naked eyes A suspension is unstable. For example:-Chalk powder and water, wheat flour and water
1) 2) 3)
1) 2) 3)
OR A 21: i) Air is a homogeneous mixture of a number of gases. Gases like oxygen, carbon dioxide etc are mixed in nitrogen gas. Thus, air is a homogeneous mixture of gas in gas and a homogeneous mixture of two or more substances is called a solution. Therefore, air is solution. ii) Cooking oil and water are two immiscible liquids. So, we will pour the mixture in a separating funnel and keep it undisturbed for a while.
The two liquids have different densities. So, cooking oil being lighter will float on water. Open the stopcock of the funnel and pour out the lower layer of the water. Close the stopcock as the oil reaches the stop-cock. In this way we can separate two immiscible liquids by using a separating funnel.
A 22: i) Newton’s first law of motion states that an object continues to be in a state of rest or uniform motion along a straight line unless acted upon by an unbalanced force. ii) Seat belts should be worn to avoid accidents due to sudden application of brakes. While driving or traveling in a car, we tend to remain at rest with respect to the seat. On sudden application of brakes, the car slows down or stops but our body continues in the same state of motion due to its inertia. Thus our body falls forward and may get injured due to impact or collision with the panels in front. Wearing safety belts exerts a force on our body to make the forward motion slower.
iii) The expression for the second law of motion is : F = ma or F = m(v – u) t or Ft = mv – mu Here, when F = 0, v = u for whatever time t is taken, which means the object will continue to move with uniform velocity u, throughout the time ‘t’ if no external unbalanced force acts on it. Also, if the object is at rest i.e. u = 0 then v = 0. This means the object will remain at rest if no external unbalanced force acts on it. Thus, we can state the first law of motion from the mathematical expression for the second law of motion. OR
A 22: i) It is advisable to tie any luggage kept on the roof of a bus to avoid it from falling forward when brakes are applied. When the bus is in motion, the luggage tends to remain in the state of rest with respect to the roof of a bus. When sudden brakes are applied to the bus, the bus slows down or stop but the luggage continues to be in its state of motion because of its inertia.
Therefore it may fall forward in front of the vehicle. Tying the luggage provides a force which opposes the forward motion of the luggage, thus helping it to not fall down. ii) Given : Mass of bullet = 0.01 kg, Mass of plank = 0.06 kg Total momentum before collision = (mass of bullet × velocity of bullet) + (mass of plank × velocity of plank) = (0.01 kg × 50 m/s) + (0.06 kg × 0) = 0.5 kg m/s Total momentum after collision = (mass of bullet + mass of plank) × velocity. = (0.01 + 0.06) v = (0.07) × v According to the law of conservation of momentum, Total momentum before collision = Total momentum after collision 0.5 = 0.07 × v v = 7.14 m/s Thus, the plank and the bullet will move with a velocity of 7.14 m/s
A 23: i) The acceleration of an object is the change in velocity per unit time It is given by the formula a = v – u where ‘u’ is the initial velocity of the object, ‘v’ is final velocity t of the object moving with uniform acceleration a for time ‘t ii) Given:Initial velocity (u) = 72 km/h = 20 m/s Final velocity (v) = 180 km/h = 50 m/s Time (t) = 20 S Using a = v – u , we get t a = 50 – 20 20 = 30 20 a = 1.5 m/s2 Thus acceleration of the train = 1.5 m/s2 We know, s = ut + 1 at 2 2 s = 20 × 20 + 1 × (1.5) (20) × (20) 2 = 400 + 300 = 700 m s = 0.7 km OR
A 23: i)
ii) Initial velocity of object B = OQ = 40 m/s Final velocity of object B = 0 m/s ( object B comes to rest) Time interval = OS Acceleration = Change in velocity time taken = 40 – 0 50 =4 5 = 0.8 m/s2 Thus, acceleration of object B = 0.8 m/s2 iii) Distance travelled by object A = s1 = Area of trapezium OPRS s1 = (OP + RS) × OS 2 = (20 + 60) × (50) 2 = 2000 m Distance travelled by object B = s2 = Area
= 1000 m Thus, distance travelled by object A = 2000 m and by object B = 1000 m A 24: i) Mixed farming is a system of farming on a particular farm which includes crop production combined with raising of livestock. ii) Italian variety of bee (A. mellifera) is commonly used for honey production because these bees have high honey collection capacity. They sting less. They stay in the given beehive for a longer period of time and breed well. iii) The quality and taste of honey depends upon the pasturage or the flowers available for the bees for nectar and pollen collection the kind of flowers available in the pasturage.
OR A 24: i) The internal parasites are the parasites that enter inside the body of cattle and harm their internal organs while external parasites live on the skin. ii) Internal parasites a) b) Worms Flukes Organs affected Stomach and intestine Liver
iii) The two qualities desirable in a cattle are a)Good resistance to diseases
b) Long lactation periods iv) Local breed of cattle – Sahiwal Exotic breed of cattle – Jersey
A 25: 1) Carbohydrate.
A 26: 3) It is a corrosive acid.
A 27: 2) Colloid.
A 28: 4) Milk and sugar solution.
A 29: 4) B and D.
A 30: 2) A – Sulphur dissolves and iron particles settle down. B – Nothing
dissolves. A 31: 1) Compound. A 32: 3) A 33: 3) A toothpick.
A 34: 2) Vacuole.
A 35: 4) Osmosis. A 36: 2) 100 o C.
A 37: 2) A – 2 – 3 cm above the surface of water. B – Slightly Dipped in the ice pieces.
A 38: 3) Earthworms.
A 39: 2) Parenchyma.
A 40: 2) B A 41: 4) Student D. A 42: 1) (F1 + F2) – F3 Reason: F1 and F2 are in same direction, so they will add up. F3 is in a opposite direction of F1 and F2 so, we take the net force as (F1 + F2 ) – F3.