RBSE 10th Science Model Paper Set 3 with Answers in English

Students must start practicing the questions from RBSE 10th Science Model Papers Set 3 with Answers in English Medium provided here.

RBSE Class 10 Science Model Paper Set 3 with Answers in English

Time: 2:45 Hours
Maximum Marks: 80

General Instructions to the Examinees:

• Candidate must write first his/her roll no. on the question paper compulsorily.
• All the questions are compulsory.
• Write the answer to each question in the given answer book only.
• For questions having more than one part the answer to those parts are to be written together in continuity.

Part – A

1. Multiple Choice Questions:
Choose the correct alternative for the following questions and write them in the answer book.

(i) Select the correct statement: [1]
(a) Heterotrophs do not synthesize their own food.
(b) Heterotrophs utilize solar energy for photosynthesis
(c) Heterotrophs synthesize their own food.
(d) Heterotrophs are capable of converting carbon dioxide and water into carbohydrates
Answer:
(a) Heterotrophs do not synthesize their own food.

(ii) The exit of unabsorbed food material is regulated by : [1]
(a) liver
(b) anus
(c) small intestine
(d) anal sphincter
Answer:
(d) anal sphincter

(iii) Roots of plants are: [1]
(a) positively geotropic
(b) negatively geotropic
(c) positively phototropic
(d) none of these
Answer:
(a) positively geotropic

(iv) Which of the following acts as both endocrine and exocrine gland ? [1]
(a) pancreas
(b) thyroid
(c) adrenal
(d) liver
Answer:
(a) pancreas

(v) To get 2 Ω resistance using only 6 Ω resistors the number of them required is: [1]
(a) 2
(b) 3
(c) 4
(d) 6
Answer:
(b) 3

(vi) If R₁ and R₂ be the resistance of the filament of 40 W and 60 W respectively operating at 220 V, then: [1]
(a) R₁ < R₂
(b) R₁ < R₂
(c) R₁ = R₂
(d) R₁ ≥ R₂
Answer:
(b) R₁ < R₂

(vii) light travel faateet in: [1]
(a) water
(b) air
(C) glace
(d) diamond
Answer:
(b) air

(viii) A reflecting surface le curved outwards. The mirror formed will be: [1]
(a) plane
(b) concave
(c) convex
(d) cylindrical
Answer:
(c) convex

(ix) At the time nf chart circuit the current in the circuit: I
(a) reduced substantially
(b) doce not change
(c) increases heavily
(d) varies continuously
Answer:
(c) increases heavily

(x) Which of the following are exothermic proceses? [1]
(i) reaction of water with quick lime
(ii) dilution otan acid
(iii evaporation of water
(iv) sublimation of camphor (crystals)
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(iv) (iii) and (iv)
Answer:
(a) (i) and (ii)

(xi) Which one of these is an organic acid? [1]
(a) citric acid
(b) hydrochloric acid
(c) lactic acid
(d) both (a) and (C)
Answer:
(d) both (a) and (C)

(xii) solution of FeSO₄ in water is: [1]
(a) colourlene
(b) blue
(c) light green
(d) brown
Answer:
(c) light green

2. Fill in the blanks:

(i) …………………. of plants are positively phototropic. [1]
Answer:
Shoots

(ii) Green plants are …………………… in their mode of nutrition. [1]
Answer:
Autotrophic

(iii) Coliform is found in ………………….. . [1]
Answer:
Intestine

(iv) Kulhs’ the ancient water harvesting structure were made in ……………… . [1]
Answer:
Himachal Pradesh

(v) The speed of light in vacuum is …………………….. . [1]
Answer:
3 × 10⁸ m/s

(vi) In an electric circuit, a device called ……………………. is often used to change the resistance
in the circuit. [1]
Answer:
Rheostat

3. Very Short Answer Type Questions (Answer the questions in one word or one line)

(i) What name is given to the tuft of capillaries present in the cup of bowman’s capsule ? [1]
Answer:
Glomerulus

(ii) What are the two parts of the nervous system of higher animals ? [1]
Answer:
Central nervous system and peripheral nervous system

(iii) Name a material wfiich can lead to biomagnification. [1]
Answer:
DDT

(iv) What is the procesl of growing of forests in an area which has been cleared of forest called? [1]
Answer:
Reforestation

(v) List any two traditional systems of water harvesting. [1]
Answer:
Ponds and small earthen dams

(vi) What will be the effect on resitance of the wire when the cross section of the wire is doubled ? [1]
Answer:
Resistance will become half when the cross section area of wire is doubled

(vii) How can it be shown that magnetic field exits around a wire carrying current ? [1]
Answer:
By using magnetic compass which shows deflection

(viii) What will you do if you see a person coming in contact with a live wire ? [1]
Answer:
Such a person should be provided with an insulated support of wood, plastic or rubber

(ix) Name the acid present in tamarind. [1]
Answer:
Tartaric acid

(x) At what pH in the mouth is tooth decay faster and why ? [1]
Answer:
When the pH in the mouth falls below 5.5, the basic compound of tooth enamel is attacked by acid

(xi) What is the name given to a reaction between an acid and a base ? [1]
Answer:
Neutralization reaction

(xii) Which one has a higher pH value.
(i) Blood or distilled water
(ii) Gastric Juice or lemon Juice. [1]
Answer:
(i) Blood
(ii) Gastric juice

Part – B

Short Answer Type Questions – Write the answer of questions no. 4 to 16 (Word limit 50 words)

Question 4.
What is the function of digestive enzymes [2]
Answer:
Digestive enzymes are biological catalysts. They convert complex, larger and insoluble food molecules into simple, smaller and soluble molecules. In simple words digestive enzymes make the food usable by the organism.

Question 5.
What type of progeny was obtained by Mendel in Fi generations when he crossed the tall and short plants ? Draw only diagram. [2]
Answer:

Question 6.
Do genetic combinations of mothers plays a significant role in determining the sex of a new bom ? [2]
Answer:
No genetic combination of mothers do not play significant role in determining the sex of a new bom. Mothers are homogametic, i.e. they produce only one type of egg. All children inherit only X sex chromosome from the mother. The sex of the new born is determined by the type of sperm (X or Y) contributed by father.

Question 7.
Explain the role of UV radiation in producing ozone layer. [2]
Answer:
Ozone at the higher levels of the atmosphere is a product of UV radiation acting on oxygen (O₂) molecule. The higher energy UV radiations split apart some molecular oxygen (O₂) into free oxygen (O) atoms. These atoms then combine with the molecular oxygen to form ozone.

Question 8.
List four properties of the image formed by a plane mijrrpr. [2]
Answer:

• It is always virtual and erect.
• Its size is equal to that of the object.
• It is formed at the same distance behind the mirror as the object is infront of the mirror.
• It is laterally inverted.

Question 9.
How is heating effect of eleptric current used in an electric bulb ? [2]
Answer:
Electric bulb works on the principle of heating effect of electric current. When electric current passes through a very thin, high resistance tungsten filament of an electric bulb, the filament becomes white hot and emits light.

Question 10.
How much work is done in moving a charge of magnitude 3C across two points having a potential difference of 12 V ? [2]
Answer:
Q = 3 C, V = 12 V
V= \(\frac{\mathrm{W}}{\mathrm{Q}}\)
∴ W = VQ = 12 × 3 = 16 J

Question 11.
State and explain Maxwell‘s right-hand thumb rule. [2]
Answer:
According to Maxwell’s right hand thumb rule, imagine you are grasping the current¬carrying wire in your right hand so that your thumb points in the direction of current, then the direction in which your fingers encircle the wire will give the direction of magnetic field lines around the wire.

Question 12.
When silver nitrate is added to sea water, a white precipitate is formed. Explain. [2]
Answer:
Sea water contains dissolved chlorides of Calcium and Magnesium. These react with Silver nitrate to form Silver chloride by double displacement reaction. Silver chloride is insoluble in water and thus, appears as a white precipitate. 2AgNO₃ + CaCl₂ → 2AgCl ↓+ Ca(NO₃)₂

Question 13.
Why is respiration considered an exothermic reaction ? Explain. [2]
Answer:
Rice, potatoes and bread contain carbohydrates. During digestion, these carbohy-drates are broken down into simpler substances called glucose. This glucose combines with oxygen in the cells of our body and provides energy. The special name of this reaction is respiration. Thus, respiration is an exothermic process because energy is produced during this process.

Question 14.
State two ways to prevent the rusting of iron. [2]
Answer:
Two ways to prevent the rusting of iron are :
(i) Oiling, greasing or painting: By applying oil, grease, or paint, the surface becomes waterproof and the moisture and oxygen in the air cannot come into direct contact with iron. Hence, rusting is prevented.

(ii) Galvanisation: An iron article is coated with a layer of Zinc metal, which prevents the iron from coming in contact with oxygen and moisture. Hence, rusting is prevented.

Question 15.
Differentiate between metals and non-metals on the basis of their chemical properties. [2]
Answer:

Metals	Non-metals
Metals usually have 1-3 electrons in their outermost shell.	Non-metals usually have 4-8 electrons in their outermost shell.
They lose their valence electrons easily.	They gain or share valence electrons easily.
They form oxides that are basic.	They form oxides that are acidic.
They are good reducing agents.	They are good oxidizing agents.
Normally produce cations i.e., they are electropositive.	Normally produce anions, i.e. they are electronegative.

Question 16.
Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron). [2]
Answer:
Copper does not react with cold water, hot water, or steam. However, iron reacts with steam. If the hot water tanks are made of steel (an alloy of iron), then iron would react vigorously with the steam formed from hot water.

Part – C

Long Answer Type Questions – Write the answer of questions 17 to 20 (Word limit 100 words)

Question 17.
List the role of each of the following in our digestive system.
(a) Muscles of stomach wall
(b) Hydrochloric acid
(c) Mucus [3]
OR
With the help of neat labelled diagram show how amoeba captures its food. What is the mode of nutrition in amoeba? [3]
Answer:
(a) Muscles of stomach: They bring about churning movement that breaks food into small particles and mixes it with gastric juice.
(b) Hydrochloric acid: It is a gastric secretion which softens, sterilises and acidifies the food for action of enzyme pepsin.
(c) Mucus: It lubricates the food passing through the alimentary canal and protects the wall of digestive tract from digestive enzymes.

Question 18.
What is the phenotypic ratio obtained by Mendel in a monohybrid cross ? Answer with the help of a digram. [3]
OR
Give an example of characteristics being used to determine how close two species are in evolutionary terms. [3]
Answer:
Mendel’s monohybrid cross’s phenotypic ratio is 3 : 1. A monohybrid cross happens when fertilisation occurs between two true-breeding parents who differ exclusively in the feature being examined and the resulting offspring are termed monohybrids. Mendel expermented with seven different forms of monohybrid crosses, each including opposing features for various phenotypes. The Fi offspring of such crosses all had one parent’s phenotype, but the F2 offspring had a 3 : 1 phenotypic ratio. Mendel hypothesised that each parent in a monohybrid cross provided one amongst two paired unit factors towards each offspring and that any potential combination of unit factors seemed equally probable.

Question 19.
How will you find out the direction of the magnetic field produced by a current-carrying conductor ? [3]
OR
What is a fuse wire ? What is the advantage and disadvantage of using a thick fuse wire ? [3]
Answer:
The direction of lines of force of the magnetic field produced by a straight wire carrying current is obtained by Maxwell’s right ‘ hand thumb rule. According to Maxwell’s right hand thumb rule, “Imagine that the current carrying wire is in the right hand so that the thumb points in the direction of current, then the direction in which the fingers encircle the wire gives the direction of magnetic lines of force around the wire.

Imagine a current carrying wire AB in which the current is flowing vertically upwards. To find out the direction of magnetic lines of force produced by this current, we imagine the wire AB to be held in the right hand, so that the thumb points in the direction of current towards A. Now, the direction in which the fingers are folded gives the direction of the lines of force. In this case the fingers are folded in the anticlockwise direction, so the magnetic lines of force are also in the anticlockwise direction.

Question 20.
Write the balanced chemical equations for the following reactions and identify
the type of reaction in each case.
(a) Nitrogen gas is treated with hydrogen gas in the presence of a catalyst at 773 K to form ammonia gas.
(b) Sodium hydroxide solution is treated with Acetic acid to form Sodium acetate and water.
(c) Ethanol is warmed with ethanoic acid to form Ethyl acetate in the presence of concentrated H₂SO₄.
(d) Ethene is burnt in the presence of oxygen to form Carbon dioxide, water
and releases heat and light. [3]
OR
Write the balanced chemical equations for the following reactions and identify
the type of reaction in each case.
(a) Thermite reaction, iron (III) oxide reacts with aluminium and gives molten Iron and Aluminium oxide.
(b) Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid Magnesium nitride.
(c) Chlorine gas is passed in an aqueous Potassium iodide solution to form Potassium chloride solution and solid iodine. [3]
Answer:

(b) NaOH(ag) + CH₃COOH(aq) → CH₃COONa(aq) + H₂Q(l)
[Double displacement reaction/Neutralisation reaction]

[Double displacement reaction/ Esterification reaction]
(d) CH(g) + 3O(g) → 2CO(g) + 2HO(g) + Heat + Light [Redox reaction/Combustion reaction]

Part – D

Eassy Type Questions – Write the answers of question 21 to 23 (Word limit 250 words)

Question 21.
How do leaves of plants help in excretion ? Explain briefly. [4]
OR
Describe the structure and function of a nephron. [4]
Answer:
The cellular respiration, photosynthesis, and other metabolic reactions produce a lot of excretory products in plants. Carbon dioxide, excess water produced during respiration and nitrogenous compounds produced during protein metabolism are the major excretory products in plants. Plants produce two gaseous waste products, i.e. oxygen during photosynthesis and carbon dioxide during respiration. Excretion of gaseous waste in plants takes place through stomatal pores on leaves. Oxygen released during photosynthesis is used for respiration while carbon dioxide released during respiration is used for photosynthesis.

Excess of water is also excreted from the plant body through the stomatal pores and from the surfaces of fruits and stems. The process of elimination of water is called transpiration. Leaves help in excretion through a process called abscission. Abscission is falling of old and yellow leaves, By the help of this process plants get rid of toxins etc. Many plants store waste materials in the vacuoles of mesophyll cells and epidermal cells. When old leaves fall, the waste materials are excreted along with the leaves. Other than gaseous wastes, metabolism in plants also generates organic by-products. These wastes are stored in different forms in different parts. The gums, oils, latex, resins, etc. are some waste products stored in plant parts like barks, stems, leaves, etc. Eventually, plants shed off these parts.

Question 22.
It is desired to obtain an erect image of an object, using a concave mirror of focal length 20 cm.
(i) What should be the range of distance of the object from the mirror ?
(ii) Will the image be bigger or smaller than the object?
(iii) Draw a ray diagram to show the image formation in this case. [4]
OR
One half a convex lens of focal length of 20 cm is covered with a black paper.
(i) Will the lens produce a complete image of the object.
(ii) Show the formation of image of an object placed at 2F, of such covered lens with the help of a diagram.
(iii) How will the intensity of the image formed by half-covered lens compare
with non-covered lens? [4]
Answer:
(i) Range of the object distance is 0 to 20 cm from the pole, (ii) Image will be bigger than the object.
(ii) Image will be bigger than the object.
(iii)

Question 23.
A milkman adds a very small amount of baking soda to fresh milk. Why does this milk take a longer time to set as curd ?
Mention the nature of toothpastes. How do they prevent decay ? [4]
OR
Explain the following chemical properties of acid with the help of balanced chemical equations only. [4]
(i) When an acid reacts with a metal carbonate.
(ii) When an acid reacts with a metal bicarbonate.
(iii) When an acid reacts with a metal oxide.
(b) You are given three solutions A, B and C with pH values 2, 10 and 13 respectively. Write which solution has more hydrogen ion concentration among the three and state the nature ‘acidic or basic’ of each solution. [4]
Answer:
(a) It takes a longer time to set as curd because bacteria do not work well in presence of sodium hydrogen carbonate, i. e. fermentation will take place slowly.
(b) Tooth pastes are basic in nature. They neutralize the acid formed in mouth which causes tooth decay.