Science Olympiad Model Test Paper - 3 | Olympiad Preparation for Class 10 PDF Download

Ans: (b)
The fig. (X) is similar to Form III. So, when the sheet in fig. (X) is folded to form a cube, then 'F' appears opposite 'B', 'E' appears opposite 'C' and 'A' appears opposite 'D' Therefore, the cube in fig. (1) which shows 'F' adjacent to 'B' the cube in fig. (3) which shows 'E' adjacent to 'C' and the cube in fig. (4) which shows 'A' adjacent to 'D' cannot be formed. Hence, only the cube in fig.(2) can be formed.

Ans: (a)
The figure gets divided into eight equal parts.

Ans: (c)

• The coding system involves shifting each letter in the word by a certain number of positions in the alphabet.
• For example, in CARING to EDVGKC, each letter is shifted forward by a specific pattern.
• Applying the same pattern to BASKET, we find that it translates to DDWIBP.
• This means that the letters in BASKET are also shifted in a similar manner as in CARING.

Ans: (b)
The symbols move in the sequence. Also, the arrow rotates 135^o anti-clockwise; the trapezium gets vertically inverted and the pin-shaped symbol rotates 90^o clockwise.

Ans: (c)
The figure may be labelled as shown.

The simplest triangles are AHG, AIG, AIB, JFE, CJE and CED i.e. 6 in number.
The triangles composed of two components each are ABG, CFE, ACJ and EGI i.e. 4 in number.
The triangles composed of three components each are ACE, AGE and CFD i.e. 3 in number.
There is only one triangle i.e. AHE composed of four components.
Therefore, There are 6 + 4 + 3 + 1 = 14 triangles in the given figure.

Ans: (d)
The upper part of the figure gets vertically inverted.

Ans: (d)
The figure may be labelled as shown.

Ans: (c)

• To solve the equation, we need to find the correct combination of operators that will make the equation true.
• By swapping the operators × and +, the equation becomes: 8 + 7 – 15 ÷ 5 + 3.
• Calculating this gives us: 15 – 3 + 3 = 6, which is correct.
• Thus, the correct answer is to interchange × and +.

Ans: (c)
The figure is enclosed in a new figure with one more number of sides, in such a way that the upper vertex of the two figures coincides.

Ans: (b)
The figure may be labelled as shown.

The simplest triangles are AGH, GFO, LFO, DJK, EKP, PEL and IMN i.e. 7 in number.
The triangles having two components each are GFL, KEL, AMO, NDP, BHN, CMJ, NEJ and HFM i.e. 8 in number.
The triangles having three components each are IOE, IFP, BIF and CEI i.e. 4 in number.
The triangles having four components each are ANE and DMF i.e. 2 in number.
The triangles having five components each are FCK, BGE and ADL i.e. 3 in number.
The triangles having six components each are BPF, COE, DHF and AJE i.e. 4 in number.
Total number of triangles in the figure = 7 + 8 + 4 + 2 + 3 + 4 = 28.

Ans: (a)

• Statement 1 is correct because a convex mirror always produces a virtual image that is upright, leading to a positive magnification. In contrast, a concave mirror can produce both real and virtual images, resulting in either positive or negative magnification.
• Statement 2 is also correct as the sign of magnification indeed depends on the sign convention used in optics.
• Since both statements are true and statement 2 explains statement 1, option (a) is the correct choice.

Ans: (b)

• The gravitational force experienced by an object in orbit depends on its distance from the center of the Earth.
• Using the formula for gravitational force, we find that the force on the satellite is proportional to the mass and inversely proportional to the square of the distance from the Earth's center.
• At a distance of 3/2 RE, the gravitational pull is reduced compared to the surface, specifically by a factor of (1/(3/2)^2), which equals 4/9.
• Thus, the gravitational pull on the satellite is 300 kg * (10 N * 4/9) = 1333 N.

Ans: (c)
Amputation is a physical condition and it does not affect the DNA. Hence it can’t be inherited by the progeny. 

Ans: (a)
The pairs in the question are formed based on the artificial selection of cabbage that leads to the development of various vegetables. The plant and plant parts that humans consume are matched together. Kales -Flower is the wrong answer and we consume the leaves of Kales.

Ans: (b)
Males only have one Y chromosome. The other one is an X chromosome inherited from the mother. 

Ans: (d)
Speciation occurs when a species is separated by various factors such as genetic features or geographical factors such as mountains, rivers, islands etc. Such factors contribute to the evolution of existing species to adapt to their present environment which may lead to the development of new species.

Ans: (a)

• The straight wire carrying current generates a magnetic field. This magnetic field interacts with the compass needle, causing it to deflect.
• The compass needle aligns itself with the magnetic field lines. This means that the needle will point in a direction that is tangential to an imaginary circle around the wire.
• Thus, statement (i) is true because the wire does cause a noticeable deflection, and statement (ii) is also true as the needle's alignment is indeed tangential to the circle.
• However, since the question asks for the correct options, only statement (i) is explicitly mentioned as correct in the answer choice.

Ans: (b)
The graphical representation depicts the phenomenon of natural selection. In the initial population, the blue dots were dominant but after many generations, they went extinct and red dots took over. 

Ans: (b)

• The boy walks 80 cm for each step, and after 60 steps, he covers a total distance of 4800 cm or 48 m.
• Since he turns 90° randomly, the maximum displacement occurs when he moves in a square pattern, effectively forming a diagonal.
• The maximum displacement can be calculated using the formula for the diagonal of a square, which is side√2. Here, the side is 24 m (since he can effectively cover 24 steps in one direction).
• Thus, the maximum displacement is 24√2 m from the starting point.

Ans: (b)
The main limitation of the Dobereiner's classification was that all the known elements could not be classified into triads on the basis of their properties.
Only three triads were identified:
1. Triad of alkali metals
2. Triad of alkaline earth metals
3. Triad of halogens.

Ans: (d)

• Statement 1 is incorrect because sound does not travel uniformly in all directions; it can be affected by the environment.
• Statement 2 is also incorrect as sound waves transfer energy, but they do not transfer matter.
• Thus, both statements are false, making option (d) the correct choice.
• Understanding sound propagation is essential; it involves energy transfer, not matter transfer.

Ans: (d)
A balanced equation should have equal number of atoms of each element on each side of the equation.
All the elements besides Fe are already balanced.
The balanced equation shows that 3 moles of Fe react with 4 moles of H₂O to produce 1 mole of Fe₃O₄ and 4 moles of H₂.

Ans: (b)
Gibberellins were discovered in 1926 by a Japanese scientist, Eiichi Kurosawa, studying bakanae, the "foolish seedling" disease in rice. It was first isolated in 1935 by Teijiro Yabuta and Sumuki, from fungal strain (Gibberella fujikuroi) provided by Kurosawa.  

Ans: (c)
The primary role of hydrochloric acid is to sterilise the food you eat and to prevent harmful bacteria from entering the GI tract. HCl also triggers the release of enzymes such as pepsin, which are essential for the digestion of protein.  

Ans: (a)

• The key observation from Rutherford's experiment was that most α-particles went through the gold foil without any deflection.
• Nearly 99% of the particles passed straight through, indicating that the atom is mostly empty space.
• Only a small fraction of particles were deflected at larger angles, and very few (about one in 12000) actually rebounded.
• Thus, the statement that most α-particles were deflected by small angles is incorrect.

Ans: (a)
Capillaries are the smallest of the body's blood vessels. They are only one cell thick, and they are the site of the transfer of oxygen and other nutrients from the bloodstream to other tissues in the body. They also collect carbon dioxide waste materials and fluids for return to the veins.

Ans: (a)
u = -15 cm, f = +12 cm 
Using lens formula, 

Ans: (c)

• The correct answer is (c) because a separating funnel is not typically used for a mixture of acetone and water. Instead, this mixture can be separated using distillation due to the different boiling points of the components.
• On the other hand, centrifugation is correctly used to separate cream from milk, and chromatography is effective for separating different components of a food sample.
• Crystallization is indeed the right method for separating crystals of alum from an impure sample, making the other options valid.

Ans: (a)
Advanced sunrise and delayed sunset are due to atmospheric refraction. 

Ans: (a)

• Both statements are correct: Ethanol does indeed convert to ethanoic acid when heated with alkaline KMnO₄.
• Oxidizing agent: Alkaline potassium permanganate acts as an oxidizing agent, which means it helps in adding oxygen to ethanol.
• Correct explanation: Statement 2 accurately explains why statement 1 is true, as it describes the process of oxidation.
• Conclusion: Therefore, both statements are true, and statement 2 correctly explains statement 1.

Ans: (c)

• Statement I is true because the molar mass of He is 4 g/mol, so 48 g of He equals 12 moles, while 23 g of Na (molar mass 23 g/mol) equals 1 mole.
• Statement II is incorrect; 8 g of O₂ equals 0.25 moles, which is not 2.5 × 10²³ molecules.
• Statement III is correct; 4.8 moles of nitrogen (molar mass 14 g/mol) equals 67.2 g, not 87.2 g.
• Statement IV is true; 0.1 moles of carbon equals 6.022 × 10²² atoms.

Ans: (c)

• This statement shows the Law of constant proportions, which states that a chemical compound always contains its component elements in fixed ratio by mass.
• In ammonia, the mass ratio of nitrogen to hydrogen is consistently 14:3, no matter how the ammonia is produced.
• This principle highlights that the composition of a pure substance is always the same, which is a key concept in chemistry.
• Other laws mentioned do not apply here as they deal with different aspects of chemical reactions and compositions.

Ans: (a)
A spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. The description given is of fungal spores.

Ans: (d)

• The mass number of an atom is the total number of protons and neutrons in its nucleus.
• A dipositive ion means the atom has lost two electrons, so it originally had 12 electrons (10 + 2).
• If it has 10 electrons, it must have 12 protons (since the number of protons equals the number of electrons in a neutral atom).
• Thus, the mass number is calculated as protons (12) + neutrons (12) = 24.

Ans: (b)

• Mendel's experiments focused on dominant traits in pea plants.
• The terminal position of flowers on the stem was not a dominant trait he studied.
• Traits like tall stem, yellow seeds, and violet flowers were identified as dominant.
• Understanding these traits helped establish the foundation of genetics.

Ans: (c)

• Reflex action is a quick, automatic response to a stimulus, which is correctly stated in (i).
• However, (ii) is incorrect because sensory neurons actually carry signals from the body to the spinal cord, not the other way around.
• (iii) is also incorrect as motor neurons carry signals from the spinal cord to the muscles, not from receptors to the spinal cord.
• Thus, the only correct statement is (i), making (c) the right answer.

Ans: (a)
The hardy lichens are useful bio-indicators for air pollution, especially sulphur dioxide pollution, since they derive their water and essential nutrients mainly from the atmosphere rather than from the soil.  

Ans: (b)
The cardiac sphincter, at the upper portion (cardia) of the stomach, prevents the acidic contents of the stomach from moving upward into the esophagus.  

Ans: (a)
Glucose is broken down by the process of glycolysis. This is the common pathway for both aerobic and anaerobic conditions. Under aerobic conditions, pyruvate formed enters the Kreb's cycle. Under anaerobic conditions, pyruvate is converted into lactate in muscles. 

Ans: (a)
Urea is the principal nitrogenous compound which is excreted by the humans. It is synthesised in the liver by urea cycle but excreted via kidneys.  

Ans: (b)
v = - 25 cm, f = 10 cm

Ans: (b)

• Both statements are accurate. Chlorofluorocarbons (CFCs) are indeed the main chemicals that lead to the depletion of the ozone layer.
• Additionally, chlorine and nitrous oxide also play a significant role in damaging the ozone layer.
• This means that both statements correctly identify the harmful substances affecting the ozone layer.
• Thus, the correct option is that both statements are true.

Ans: (b)

• Pellagra is a deficiency disease caused by a lack of niacin (vitamin B3) in the diet.
• It leads to symptoms such as dermatitis, diarrhea, and dementia.
• In contrast, Filariasis, Conjunctivitis, and Sleeping sickness are not caused by nutrient deficiencies.
• Understanding these diseases helps in recognizing the importance of a balanced diet for health.

Ans: (b)

• The parent plants are smooth green (SSGG) and wrinkled yellow (ssgg).
• The F₁ generation will all be smooth green (SsGg) since smooth and green are dominant traits.
• When F₁ plants are self-crossed, the F₂ generation will show a typical Mendelian ratio of 9:3:3:1 for the traits.
• For wrinkled green seeds, the expected ratio is 3 out of 16 total combinations, which translates to (3/16) * 160 = 30 plants.

Ans: (d)

• The Kyoto Protocol was actually adopted in 1997, not 1982, making it the incorrect match.
• The Montreal Protocol was established in 1987 to protect the ozone layer.
• The Ganga Action Plan was initiated in 1986 to clean the Ganges River.
• The Chipko Movement, which started in 1973, focused on environmental conservation and tree protection.

Ans: (c)

• Statement I: Compounds (i) Ethanol and (v) Propanal have different functional groups; hence, this statement is incorrect.
• Statement II: Compounds (vi) Propanone and (vii) Butanone are both ketones, making them part of the same homologous series, so this statement is correct.
• Statement III: Compound (iii) Bromopropane does not have multiple bonds; it is a saturated compound, making this statement incorrect.
• Statement IV: Ethanoic acid does react with ethanol to form an ester in the presence of an acid catalyst, confirming this statement is correct.

In summary, the correct statements are II and IV, which is why the answer is (c).

Ans: (d)

• The compound that reacts with hot concentrated sulfuric acid to form ethene is ethanol.
• When ethanol is heated with sulfuric acid, it undergoes dehydration, losing a water molecule to form ethene.
• Other options like propanal, propanol, and ethanoic acid do not produce ethene under these conditions.
• This reaction is a common method in organic chemistry to produce alkenes from alcohols.

Ans: (c)
Septum is responsible for maintaining rigidity and support to the heart and it helps in proper functioning of the heart.
Inferior vena cava carries de-oxygenated blood from the lower half of the body to the right atrium of the heart. Pulmonary artery is responsible for transporting oxygen-depleted blood away from the heart and towards the lungs.
Left auricle receives blood from the lungs.

Ans: (a)
Ciliated epithelial tissue is found in our respiratory tract and in the Fallopian tubes of women. Ciliated epithelium contains goblet cells, which secrete mucous. This mucous, combined with the cilia on the tissue, helps move harmful particles out of our bodies to keep us healthy.

Ans: (d)
Villi are adapted for the maximum absorption of digested food molecules. This is because the folded villi greatly increase the surface area of the intestine; the villi are made of a single layer of thin cells; beneath the villi is an extensive blood capillary network to distribute the absorbed food molecules.