RBSE 10th Science Model Paper Set 2 with Answers in English

Students must start practicing the questions from RBSE 10th Science Model Papers Set 2 with Answers in English Medium provided here.

RBSE Class 10 Science Model Paper Set 2 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 autotrophic mode of nutrition requires:
(a) carbon dioxide and water
(b) chlorophyll
(c) sunlight
(d) all of these [1]
Answer:
(d) all of these

(ii) Which part of alimentary canal receives bile from the liver?
(a) stomach
(b) small intestine
(c) large intestine
(d) oesophagus [1]
Answer:
(b) small intestine

(iii) The gap between two neurons is called a:
(a) dendrite
(b) synapse
(c) axon
(d) impulse [1]
Answer:
(b) synapse

(iv) Which of the following is not associated with growth of plants:
(a) auxin
(b) gibberellins
(c) cytokinins
(d) abscisic acid [1]
Answer:
(d) abscisic acid

(v) You are given water, mustard oil, glycerine and kerosene. In which of these media a ray of light incident obliquely at same angle would bend the most?
(a) kerosene
(b) water
(c) mustard oil
(d) glycerine [1]
Answer:
(d) glycerine

(vi) A full-length image of distant tall building can definitely be seen by using:
(a) a concave mirror
(b) a convex mirror
(c) a plane mirror
(d) both concave as well as plane mirror [1]
Answer:
(b) a convex mirror

(vii) Which of the following does not represent electric power in a circuit?
(a) I²R
(b) IR²
(c) VI
(d) V²/R [1]
Answer:
(b) IR²

(viii) Unit of electric power may also be expressed as:
(a) Volt ampere
(b) Kilowatt-hour
(c) Watt-second
(d) Joule second [1]
Answer:
(a) Volt ampere

(ix) The direction of magnetic field produced by a current carrying-straight conductor can be found using:
(a) right hand. thumb rule
(b) right hand Fleming rule
(c) left hand Fleming rule
(d) right hand screw rule [1]
Answer:
(a) right hand. thumb rule

(x) Which of the following is not a physical change?
(a) boiling of water to give water vapour
(b) melting of ice to give water
(c) dissolution of salt in water
(d) combustion of Liquified Petroleum Gas (LPG) [1]
Answer:
(d) combustion of Liquified Petroleum Gas (LPG)

(xi) Which of the following property is generally not shown by metals?
(a) electrical conduction
(b) sonorous in nature
(c) dullness
(d) ductility [1]
Answer:
(c) dullness

(xii) A solution turns red litmus blue. Its pH is likely to be:
(a) 1
(b)4
(c) 5
(d) 10 [1]
Answer:
(d) 10

2. Fill in the blanks:

(i) A green pigment found in plants is called …………………………… . [1]
Answer:
Chlorophyll

(ii) The movement of shoot towards light is …………………………… . [1]
Answer:
Phototropism

(iii) …………………………….. percent of solar radiation is captured by plants. [1]
Answer:
1 %

(iv) Indira Gandhi Canal from ……………………………. dam has brought greenery to many areas of Rajasthan. [1]
Answer:
Bhakra

(v) …………………………………. mirror is used for seeing. [1]
Answer:
Plane

(vi) Voltmeter is always connected in …………………………………….. in an electric circuit. [1]
Answer:
Parallel

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

(i) What is the functional unit of a kidney? [1]
Answer:
(i) Nephron

(ii) Name the gland which produces growth hormone. [1]
Answer:
Pituitary gland

(iii) Name two groups of organisms which act as decomposers in an ecosystem. [1]
Answer:
Bacteria and Fungi

(iv) What type of bacteria inhabiting intestine of human being pollute water? [1]
Answer:
Escherichia

(v) Where will the image be formed by convex mirror if object is placed between infinity and pole of mirror? [1]
Answer:
Image formed between pole and focus behind the mirror.

(vi) How are ammeter and voltmeter connected in circuit? [1]
Answer:
Ammeter is always connected in series and voltmeter is always connected in parallel with the circuit.

(vii) What is a natural magnet? [1]
Answer:
Natural magnet is an iron ore called magnetite.

(viii) What is the direction of magnetic field lines around a magnet? [1]
Answer:
Magnetic field lines arise from north pole and go towards south pole of the magnet.

(ix) What is the pH of blood?
Answer:
Approximately 7.4

(x) Name the two synthetic indicators. [1]
Answer:
1. Phenolphthalein
2. Methyl orange.

(xi) 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.

(xii) Why does an aqueous solution of an acid conduct electricity? [1]
Answer:
Acids conduct electricity in aqueous solution due to the presence of free ions.

Part – B

Short Answer Type Questions – Write the answer of questions 4 to 16 (Word limit 50 words),

Question 4.
How is the amount of urine produced regulated? [2]
Answer:
About 180 litres of fluid is collected in human nephrons daily after filtration. But most of this water is reabsorbed by the tubule. The amount of urine produced is regulated by the process of re-absorption. If input of water is more, then there is less re-absorption of water. When water is to be conserved in the body, reabsorption increases. This is called Osmoregulation.

Question 5.
How does a monohybrid cross differ from a dihybrid cross? [2]
Answer:
Monohybrid cross tkes into consideration inheritance of one trait at a time. For example, height of the plant. On the other hand, inheritance of two characters is observed simultaneously in a dihybrid cross. For example, inheritance of colour of the seed and shape of the seed.

Question 6.
Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? [2]
Answer:
Geographical isolation will not be a major factor in the speciation of a self-pollinating plant because geographical isolation makes a species reproductively isolated from other sub-populations. But a self-pollinating plant does not depend on other plants of the species for sexual reproduction.

Question 7.
What do you mean by food chain ? [2]
Answer:
Green plants produce food in the process of photosynthesis. In other words, they convert the radiation energy of sun into food eaten by a herbivore like a deer. This deer may be eaten by a carnivore like a tiger. In this way a chain or a sequence of eating and being eaten is formed. This is called a food chain.

Question 8.
Write the laws of reflection of light.
Answer:
The reflection of light from the surface takes place according to the following two laws:

1. Incident ray reflected ray and the normal at the point of incidence, all lie in same plane.
2. The angle of incidence is equal to the angle of reflection.

Question 9.
What is the lowest total resistance that can be secured by combinations of four coils of resistance 4Ω, 8Ω, 12Ω and 24Ω? [2]
Answer:
The lowest tojal resistance is obtained when resistances are connected in parallel.
\(\frac{1}{\mathrm{R}}=\frac{1}{\mathrm{R}_{1}}+\frac{1}{\mathrm{R}_{2}}+\frac{1}{\mathrm{R}_{3}}+\frac{1}{\mathrm{R}_{4}}\)
\(\frac{1}{R}=\frac{1}{4}+\frac{1}{8}+\frac{1}{12}+\frac{1}{24}\)
\(\frac{1}{R}=\frac{6+3+2+1}{24}\)
⇒ R = \(\frac{24}{12}\) = 2 Ω

Question 10.
Explain the following:
(a) Why is the tungsten used almost exclusively for filament of electric lamps?
(b) Why are the conductors of electric heating devices, such as toasters and electric irons, made of an alloy rather than a pure metal? [2]
Answer:
(a) Due to high melting point of tungsten ( ≈3380°C), it becomes incandescent at 2400 K.
(b) ‘The resistivity of alloys are generally higher than that of pure metals of which they are made of.

Question 11.
How does a solenoid behave like a magnet? Can you determine the north and south poles of a current-carrying solenoid with the help of a bar magnet? Explain. [2]
Answer:
A current-carrying solenoid is equivalent to a bar magnet. Its polarities at ends depend upon the direction of current flowing through it. To determine the polarities of its ends, place it in a brass hook and suspend it with a long thread. By bringing a bar magnet near it and pointing the north pole of bar magnet near one of the ends of solenoid, if solenoid moves towards the bar magnet then that end of solenoid is a south pole. If solenoid moves away from the magnet, then the end of solenoid is its north pole.

Question 12.
Why does the iron nail become brownish in colour and the blue colour of Copper sulphate solution fade ? [2]
Answer:
This happens because iron displaces copper from copper sulphate solution to form iron sulphate. Iron is more reactive than copper and hence it displaces copper from copper sulphate solution.

Question 13.
What do you mean by a precipitation reaction? Explain by giving example. [2]
Answer:
A precipitation reaction is a reaction in which soluble ions of separate solutions are mixed together to form an insoluble compound that settles out of solution as a solid. That insoluble compound is called a precipitate.
For example: When CO₂ is passed through lime water, a white milky suspension is formed which is CaCO₃.

Question 14.
Why is sodium kept immersed in kerosene oil? [2]
Answer:
Sodium is a very reactive metal. It reacts with oxygen at room temperature to form sodium oxide (Na₂O). Sodium also react with moisture present in air to form sodium hydroxide. To protect sodium from air (or oxygen) and moisture, it is kept immersed in kerosene oil.

Question 15.
Draw labelled diagram of apparatus for testing the conductivity of a salt solution. [2]
Answer:

Question 16.
Why are aluminium containers used to transport nitric acid?
Answer:
Aluminium containers are used to transport nitric acid because concentrated HNO₃ renders aluminium passive by forming a thin strong protective oxide layer. This protective layer prevents further reaction with the acid.

Part- C

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

Question 17.
What are the differences between the transport of materials in xylem and phloem? [3]
OR
How are fats digested in our bodies? Where does this process take place? [3]
Answer:
differences between transport by xylem and phloem

Transport by Xylem	Transport by Phloem
1. Inorganic sub-stances like water and minerals are transported.	1. Organic food prepared in photosynthesis is transported.
2. Transport does not require energy(It takes place by simple physical forces).	2. Energy is needed for transport of food.
3. It is unidirectional (only upward transportation).	3. Movement is in both the directions (upward and downwards).
4. Xylem is mainly formed of dead- cells vessels and tracheids.	4. Phloem mainly made of living cells-sieve tube helped by companion cells.

Question 18.
Explain with the help of an example each how the following provide evidences in favour of evolution: [3]
(a) Homologous organs
(b) Analogous organs
(c) Fossils
OR
Give basic features of the mechanism of inheritance. [3]
Answer:
(a) Homologous Organs :
Those organs which have same basic structure among different types of living beings but perform different functions are called homologous organs. For example. arms of human beings and forelegs of horse, lion. etc. Their same basic structure shows that these have been evolved from some common ancestors.

(b) Analogous Organs: Those organs which have different basic structure but perform same functions in different types of living beings are known as Analogous organs. For example, wings of birds and wings of bat are analogous organs. Similarity’ in these organs is superficial and the design and structure or these organs is very different.

(c) Fossils : Fossils are the dead remains of the extinct form of liviiig beings. They provide the missing link between the species, e.g., Fossils of dinosours with feathers/fossils of prehistoric horse, etc.

Question 19.
Write the working of’DC generator with the help of labelled diagram. [3]
OR
(a) What is an electromagnet ? List any two uses.
(b) Draw a labelled diagram to show how an electromagnet is made. [3]
Answer:
Working of DC Generator :
As the coil rotates, the magnetic field linked with it, changes continuously. As a result of this, an induced e.mf. 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.
Explain the following terms with one example each :
(a) corrosion
(b) rancidity [1\(\frac{1}{2}+1 \frac{1}{2}\) = 3]
OR
Explain the following in terms of gain or loss of oxygen with two examples each:
(a) oxidation
(b) reduction [1\(\frac{1}{2}+1 \frac{1}{2}\) = 3]
Answer:
(a) Corrosion: The chemical process of slow eating up of the surfaces of metals when kept in open for a long time is called corrosion. This happen when due atmospheric gases; such as oxygen, carbon dioxide, hydrogen sulphide, water vapour, etc. come in contact with the surface of the metals, so as to convert, the metal into oxides, carbonates, sulphides, etc.

(b) Rancidity: Rancidity is a very general term and in its most general meaning, it refers to the spoilage of a food in such a way that it becomes undesirable (and usually unsafe) for consumption. During the process of oxidative rancidity, oxygen molecules interact with the structure of the oil and damage its natural structure in such a way that it can change its odour, its taste, and its hygiene and safety for consumption.

Part-D

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

Question 21.
(i) Draw a labelled digram of Human brain.
(ii) Compare and contrast nervous and harmonal mechanism for control and coordination in the animals.
(iii) Name the two components of central nervous system. [4]
OR
(i) How does the chemical coordination take place in animal ? Draw diagram.
(ii) What is the difference between a reflex action and walking. [4]
Answer:

(ii)

Nervous Mechanism	Hormonal Mechanism
Nervous mechanism involves the movement of stimulus and response information in the form of chemical and electrical impulses through specialized neuron cells.	Hormones are special chemicals produced by specialised organs. Information reaches the target organs through the bloodstream.
Nerve impulses are fast in their actions.	Hormones are slow in their actions.
Response is im-mediate in nervous control.	Response is usually slow.

(iii) Brain and Spinal cord ;

Question 22.
Define the principal focus of a concave mirror. A convex mirror used for rearview on an automobile has a radius of curvature of 3.00 m. If a bus is located at 5.00 m from the mirror. Find the position, nature and size of the image. Draw ray diagram. [4]
OR
Define lateral displacement. If the image formed by a lens for all positions of an object placed in front of it is always erect and diminished, what is the nature of this lens? Draw a ray diagram to justify your answer. If the numerical value of the power of lens is 10 D, what is its focal length? [4]
Answer:
The rays of light parallel and close to the principal axis of the mirror after reflection pass through a point on the principal axis, this point is called principal focus of the concave mirror.
Given,
Radius of curvature R = + 300 m
Distance of object u =- 500 m
Distance of image υ = ?
Height of image h’ =?

∵ f = \(\frac{\mathrm{R}}{2}=\frac{3.00 \mathrm{~m}}{2}\) = +1.50 m
Since \(\frac{1}{u}+\frac{1}{v}=\frac{1}{f}\)
or \(\frac{1}{v}=\frac{1}{f}-\frac{1}{u}\)
= \(\frac{1}{1.50}-\frac{1}{(-5.00)}\)
= \(\frac{1}{1.50}+\frac{1}{5.00}\)
⇒ ν = \(+\frac{15}{13}\) = +1.15 m
Magnification,
m = \(\frac{h^{\prime}}{h}=-\frac{v}{u}=-\frac{1.15 \mathrm{~m}}{-5.00 \mathrm{~m}} \)
= +0.23
The image is virtual, erect and smaller in size by a factor of 023.

Question 23.
(i) How is washing soda prepared from sodiun carbonate? Give its chemical equation. ‘
(ii) State the type of this salt. Name the type of hardness of water which can be removed by it.
(iii) How would you distinguish between baking power and washing soda? [4]
OR
(i) Explain the chemical change that causes corrosion in iron.
(ii) If an iron nail is left in a filled with bottle filled with boiled water, how long will it take to corrode? [4]
Answer:
(i) Washing soda is sodium carbonate containing 10 molecules of water of crystallization. It is also called Sodium carbonate decahydrate.
Na₂CO₃ + 10H₂O → Na₂CO₃. 10H₂O

(ii) Sodium carbonate is an organic salt. Sodium carbonate is the disodium salt of carbonic acid with alkalinising property. When dissolved in water, sodium carbonate forms carbonic acid and sodium hydroxide. Sodium carbonate decahydrate can remove temporary and permanent hardness from water. Sodium carbonate is soluble but calcium carbonate and magnesium carbonate are insoluble. The water is softened because it no longer contains dissolved calcium and magnesium ions in it.

(iii) The chemical formula of baking powder is sodium hydrogen carbonate (NaHCO₃), whereas, that of washing soda is sodium carbonate decahydrate (Na₂CO₃.10H₂O). Sodium hydrogen carbonate on heating gives CO₂ gas which will turn lime water milky, whereas no such gas is obtained from sodium carbonate decahydrate.