Students must start practicing the questions from RBSE 10th Science Model Papers Set 1 with Answers in English Medium provided here.
RBSE Class 10 Science Model Paper Set 1 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) The xylem of plants are responsible for : [1]
(a) transport of water
(b) transport of food
(c) transport of amino acids
(d) transport of oxygen
Answer:
(a) transport of water
(ii) In which part of the alimentary canal, food is finally digested? [1]
(a) stomach
(b) mouth cavity
(c) large intestine
(d) small intestine
Answer:
(b) mouth cavity
(iii) The movement of shoot towards light is: [1]
(a) geotropism
(b) hydrotropism
(c) chemotropism
(d) phototropism
Answer:
(d) phototropism
(iv) The brain is responsible for: [1]
(a) thinking
(b) regulating the heartbeat
(c) balancing the body
(d) all of these
Answer:
(d) all of these
(v) Which one of the following materials cannot be used to make a lens? [1]
(a) water
(b) glass
(c) plastic
(d) clay
Answer:
(d) clay
(vi) The laws of reflection hold good for: [1]
(a) plane mirror only
(b) concave mirror only
(c) convex mirror only
(d) all mirrors
Answer:
(d) all mirrors
(vii) The resistivity does not change if: [1]
(a) the material is changed
(b) the temperature is changed
(c) the shape of the resistance is changed
(d) both material and temperature are changed.
Answer:
(c) the shape of the resistance is changed
(viii) A student carries out an experiment and plots the V-I graphs of three samples of Nichrome wire with resistance R1, R2 and R3 respectively. Which of the following is true? [1]
Answer:
(a) R1=R2=R3
(b) R1>R2>R3
(c) R1<R2=R3
(d) R3>R2>R1
Answer:
(c) R1<R2=R3
(ix) Magnetic field around a current-carrying wire has : [1]
(a) circular symmetry
(b) no symmetry
(c) elliptical curves
(d) hone of these
Answer:
(a) circular symmetry
(x) Which of the following are combination reactions?
(ii) MgO + H2O → Mg (OH)2
(iii) 4Al + 3O2 → 2Al2O3
(iv) Zn + FeS04 → ZnSO4 + Fe ” .
(a) (i) and (iii)
(b) (iii) and (iv)
(c) (ii) and (iv)
(d) (ii) amd (iii)
Answer:
(d) (ii) amd (iii)
(xi) The ability of metals to be drawn into thin wire is known as: 1
(a) ductility
(b) malleability
(c) sonorously
(d) conductivity
Answer:
(a) ductility
(xii) An aqueous solution turns red litmus solution in blue. Excess addition of which of the following solution would reverse the change? [1]
(a) baking powder
(b) lime
(c) ammonium hydroxide solution
(d) hydrochloric acid
Answer:
(d) hydrochloric acid
2. Fill in the blanks: 1 x 6 = 6
(i) The opening and closing of the pore is a function of the …………………………… .[1]
Answer:
guard cells,
(ii) ………………………………. is the hunger centre. [1]
Answer:
Hypotha famous,
(iii) ………………………………….. is the ultimate source of energy for an ecosystem. [1]
Answer:
The sun,
(iv) Petroleum is a ………………………….. fuel. [1]
Answer:
fossil,
(v) Unit of power of lens is …………………… .[1]
Answer:
dioptre,
(vi) Electric fuse work on the principle of ………………………….. of electric current. [1]
Answer:
heating effect
3. Very Short Answer Type Questions (Answer the questions in one word or one line)
(i) Name the green pigment present in plants which can absorb solar energy? [1]
Answer:
Chlorophyll
(ii) In what form stimuli are received by olfactory receptors? [1]
Answer:
In the form of chemicals.
(iii) What types of organisms form the second trophic level in a food chain? [1]
Answer:
Herbivores (Primary consumers).
(iv) Which gas released by the burning of coal and petroleum adds to global warming? [1]
Answer:
Carbon dioxide.
(v) Where should an object be placed in front of a concave mirror so as to obtain its magnified erect image? [1]
Answer:
Between the pole and focus.
(vi) Why are copper wires used as connecting wire? [1]
Answer:
The electrical resistivity of copper is low, so copper wires are used as connecting wires.
(vii) How is a magnetic field around a current-carrying conductor related with current flowing through it? [1]
Answer:
Magnetic field increases with the increase in electric current i.e., B∝ I.
(viii) What is the basic cause of induced emf? [1]
Answer:
The basic cause of induced emf is the change of magnetic field in the circuit.
(ix) Name the substance which on treatment with chlorine yields bleaching powder. [1]
Answer:
Slaked lime Ca(OH)2 gives bleaching powder when treated with chlorine gas.
(x) What will happen when dry ammonia gas is passed over dry litmus paper? [1]
Answer:
There will be no changes as dry ammonia does not act as a base.
(xi) What is the optimum pH range for living organisms?
Answer:
7.0 to 7.8
(xii) How are indicators used to differentiate between an acid and a base? [1]
Answer:
By change in colour.
Part-B
Short Answer Type Questions – Write the answer of questions 4 to 16 (Word limit 50 words)
Question 4.
Why is blood circulation in human heart called double circulation? [2]
Answer:
In human beings, the blood passes through the heart twice in order to complete one cycle. It passes through the right side of the heart as deoxygenated blood and through the left side as oxygenated blood. Therefore, in human heart it is called double circulation.
Question 5.
Why are the traits acquired during the lifetime of an individual not inherited? [2]
Answer:
Traits which are acquired during the lifetime of an individual are not inherited because these are bodily or somatic changes. Somatic changes are not transferred to the next generation. Only the changes of the genetic material are transferred to the next generation. These too should be in the genetic material of gonads.
Question 6.
Outline a project which aims to find the dominant coat colour in dogs. [2]
Answer:
Information about pet dogs can be obtained easily. Make a questionnaire- Colour of the dog and bitch in parental generation. Colour of the dog in first generation. Dominant colour appears in more individuals. Also, try to collect information about the coat colour of dogs of earlier generations, i.e. grandparents.
Question 7.
What is biological magnification? Will the level of this magnification be different at different levels of the ecosystem?[2]
Answer:
Progressive inease in the concentration of harmful non-biodegradable substances at successive trophic levels of a food chain is called biological magnification. Yes, the level gradually increases. It is lowest at producer level but highest in top consumers, like human.
Question 8.
How is the refractive index of a medium related to the speed of light? Obtain an expression for refractive index of a medium with respect to another in terms of speed of light in these two media. [2]
Answer:
Refractive index (n) = \(\frac{\text { speed of light }(c)}{\text { velocity of light in the medium }(v)} \)
If υ1, is the velocity of light in a medium of refractive index n1 and υ2 is the velocity of light in another medium of refractive index n2, then
n1 = \(\frac{c}{v_{1}}\) and n2 = \(\frac{c}{v_{2}}\)
∴ n21 = \(\frac{n_{2}}{n_{1}}=\frac{c / v_{2}}{c / v_{1}}=\frac{v_{1}}{v_{2}}\).
Question 9.
An electric bulb is connected to a 220 V generator. The current is 0.50 A. What is the power of the bulb ? [2]
Answer:
Given, V =220 volt
I =0.50A
P =VI= 220 V x 0.50A
= 110J/s= 110W
Question 10.
Explain the following :
(a) Why is the series arrangement not used for domestic circuits?
(b) How does the resistance of a wire vary with its cross-sectional area? [2]
Answer:
(a) In series circuits, same current flows thén if any one of the electric appliances fails or is in off position, then all the other appliances stop working because same electric current is flowing through all of them.
(b) The resistance of a wire
(R) varies inversely as its cross-sectional area (A), i.e.
R∝ \(\frac{1}{\mathrm{~A}}\) .
Question 11.
There is either a convergence or divergence of magnetic field lines near the ends of a current-carrying straight solenoid. Give reason. [2]
Answer:
One end of the current-carrying solenoid acts like a north pole and the other end acts like a south pole. The magnetic field is stronger near the poles, therefore there is either a convergence (at south pole) or divergence (at north pole) of magnetic field lines near the ends of a current-carrying straight solenoid.
Question 12.
Oil and fat containing food items are flushed with nitrogen. Why? [2]
Answer:
In the presence of oxygen in the air, the fats present in the fatty food are oxidized to compounds which have a bad smell, i.e. the food becomes rancid. Flushing with nitrogen cuts off oxygen and protects the food from rancidity.
Question 13.
When silver nitrate is added to seawater, a white precipitate is formed. Explain. [2]
Answer:
Seat 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 14.
What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes place.[2]
Answer:
When zinc is added to a solution of iron (II) sulphate, iron gets precipitated. The light green colour of the solution fades away. The chemical reaction will be:
Question 15.
Draw the apparatus to show action of steam on a metal.
Answer:
Question 16.
Why is Al obtained only by electrolytic reduction of Alumina (pure)?[2]
Answer:
Minimum metal has a strong affinity for oxygen and the oxide of Al is Al2O3, which is a very stable oxide. Hence, ordinary chemical reducing agents are not sufficient to reduce Al2O3 to Al. Electrolytic reduction is a more powerful reduction method.
Part-C
Long Answer Type Questions – Write the answer of questions 17 to 20 (Word limit 100 words)
Question 17.
Differentiate between autotrophs and heterotrophs. [3]
QR
What is transpiration? List its two functions. [3]
Answer:
Autotrophs | Heterotrophs |
(i) Autotrophs make their own food from simple inorganic materials. | (i) They take ready-made food prepared by other organisms. |
(ii) Use energy of sun to make food in the process of photosynthesis. | (ii) Do not use light energy and there is no photosynthesis. |
(iii) Green plants are autotrophs. They transform energy. | (iii) Use chemical energy. Do not transform energy. |
(iv) They are either photoautotroph or chemoautotrophs. | (iv) They may be holozoic, parasitic or absorptive (saprotroph). |
Question 18.
What is meant by speciation? List four factors that could lead to speciation. Which of these cannot be a major factor in the speciation of a self-pollinating plant species? Give reason to justify your answer. [3]
OR
What are fossils? Describe briefly two methods of determining the age of fossils. [3]
Answer:
Speciation: The process by which new species develop from the existing species by evolution or any genetic modification of previous species is known as speciation. The important factors which could lead to the formation of new species are:
(i) Geographical Isolation of a population caused by various types of barriers like mountain ranges, rivers, sea etc. The
geographical isolation leads to reproductive isolation due to which there is no flow of genes between separated groups of population.
(ii) Genetic drift caused by drastic changes in the frequencies of particular genes by chance alone.
(iii) Variations caused in individuals due to natural selection.
(iv) Drastic change in the genes or DNA called mutation is also a cause of speciation. Reproductive isolation can not be a major factor for the speciation of a self-pollinating plant species as it does not depend on any other plant for its
reproduction process.
Question 19.
Explain the working of DC generator with the help of suitable labelled diagram.
(i) What is the function of an earthing?
(ii) Why is it necessary to earth metallic appliances? [3]
Answer:
As the coil rotates, the magnetic field linked with it changes continuously. As a result of this, an induced e.m.f. is produced. The induced emf gives rise to the flow of current.
With special design of R1 and R2, as we have taken here, direction of current during both the halves of revolution of armature is always same. This is because one brush is always in contact with arm of armature moving up and other brush is in contact with the arm of armature moving downward in the magnetic field.
Question 20.
What information do we get from a balanced chemical equation? [3]
OR
In a container, solid calcium oxide was taken and water was added slowly to it.
(a) State the two observations made in the experiment.
(b) Write the name and chemical formula of the product formed. [3]
Answer:
A balanced chemical equation gives us the following information:
- Formulae of the reactions, which take part in the chemical reaction.
- Formulae of the products formed during the chemical reaction.
- Number of moles of each reactant and product.
- Mass of each substance involved in the reaction.
- Physical state of all the reactants and products.
- Type of reaction taking place between reactions.
Part-D
Essay Type Questions – Write the answers of questions 21 to 23 (Word limit 250 words)
Question 21.
(a) Which part of the brain contains hunger centre?
(b) What is the role of the brain in reflex action.
(c) Draw labelled diagram of vertical section of human brain. [4]
OR
(a) What is Neurotransmitter.
(b) Write functions of the nervous system.
(c) Draw a labelled diagram of synapse. [4]
Answer:
(a) Hypothah’ur’us part of cerebrum.
(b) Conscious part of brain is not involved in reflex action as reflex actions are involuntary actions. Certain reflexes like breathing, coughing are controlled by hindbrain, but here too thoughts or conscious part of brain is not involved. However, as an information, it goes to brain for making memory.
(iii) Human Brain (Vertical Section)
Question 22.
(i) State two positions in which concave mirror produces magnified image of a given object.
(ii) A doctor has prescribed a corrective lens of power + 1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging? [4]
OR
(a) What is absolute refractive index?
(b) Refractive index of diamond with respect to glass is 1.6 and absolute refractive index of glass is 1.5. Find out the absolute refractive index of diamond.
(c) The refractive index of diamond is 2.42. What is the meaning of this? [4]
Answer:
(i) The two positions are:
When an object is placed between the pole(p) and focus (f’) of a concave mirror, the image formed is larger than the object(or magnified). When an object is placed between the focus (f) and centre of curvature (c) of a concave mirror, the image formed is larger than the object.
Difference between the two images
1. In case (i), the image is formed behind the mirror | In case (ii), the image is formed beyond the centre of curvature. |
2. In case (i), the image formed is virtual and erect | in case (ii), the image formed is real and inverted. |
(ii) Here, P = + 15 D
f =?
From f= \(\frac{1}{\mathrm{P}}\), f = \(\frac{100}{1.5}\) =66.7cm
As power is positive, the prescribed lens is converging or convex lens.
Question 23.
(a) How will baking soda affect the taste of the cake and why?
(b) How can baking soda be converted into baking powder?
(c) What is the role of tartaric acid added to baking soda?
(d) What is the difference between baking soda and baking powders. [4]
OR
(a) Distinguish between ‘roasting’ and ‘calcination’. Which of the two is used for sulphide ore and why?
(b) Write a chemical equation to illustrate the use of aluminium for joining cracked railway lines. [4]
Answer:
(a) Baking soda is sodium hydrogen carbonate. On heating, it is converted into sodium carbonate which is bitter in taste
(b) Baking soda can be converted into baking powder by the addition of appropriate amount of tartane acid to it.
(c) The role of tartanc acid is to neutralize sodium carbonate and cake will not taste bitter.
(d) Baking soda is sodium bicarbonate (NaHCO3) whereas baking powder is a mixture of baking soda (NaHCO3) and tartaric acid (C4H6O6).
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