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

Ans: (b)
Hence required direction is South-West.

Ans: (c)

• To find the answer, we need to look for symbols that are preceded by a number and followed by a vowel.
• In the series, the symbols that meet this condition are: % (before 7 and after e), # (before e and after J), and @ (before 5 and after K).
• Counting these, we find there are 3 symbols that fit the criteria.
• Thus, the correct answer is (c) 3.

Ans: (b)

(Option b) Amit was his father.

Since Amit has no brother, his father's son is he himself.

So, the man who is talking is the father of the man in the photograph.

Thus, the man in the photograph is his son.

Ans: (b) 6√5 m, North-East

• The policeman starts at point P and runs 14 m West.
• After turning right, he runs 12 m North.
• Then, he turns right again and runs 20 m East.
• To find the distance from point P, we can visualize his path and use the Pythagorean theorem, leading to a final distance of 6√5 m in the North-East direction.

Ans: (c)

As Justice and Parul are real brothers and their father is Solace whose brother is Moe, Moe is the uncle of Justice and Parul.

Ans: (b)

• First, we need to replace the symbols with their corresponding operations:
• For option (b): 20 ÷ 5 × 3 + 7 – 4.
• Calculating step by step: 20 ÷ 5 = 4, then 4 × 3 = 12, next 12 + 7 = 19, and finally 19 – 4 = 15.
• This confirms that option (b) is correct as it equals 15.

Ans: (d)
The movements of the child from A to E are as shown in fig Clearly, the child meets his father at E.

Now AF = (AB - FB)
= (AB - DC) = (90 - 30) m = 60m
EF = (DE - DF) = (DE - BC) = (100 - 20) m
= 80m
∴ Required distance = AE =

= 100m

Ans: (b)

• To determine the immediate neighbours of T, we first need to visualize the seating arrangement based on the given clues.
• P is fourth to the right of T, which helps us place T and P correctly.
• W is immediately left of P, and U is third to the right of Q, which gives us more positions.
• After arranging everyone, we find that the immediate neighbours of T are V and S.

Ans: 

We are required the length of AE.
We know, AE² = AF2 + EF² = 42 + 3² = 25

 AE = 5 km

Ans: (d)

• The input consists of words and numbers that are rearranged in a specific order.
• In the VIth step, the arrangement focuses on moving the numbers to the front while keeping the words in a specific sequence.
• Following the pattern, the correct VIth step is 76 56 25 14 drive enjoy ride the slowly.
• This option maintains the order of the numbers and the words as per the rearrangement rules.

Ans: (a)

• The block of mass 2m falls from a height h and compresses the spring.
• When the block hits the spring, its potential energy (mgh) is converted into spring potential energy (1/2 kx²).
• The correct equation shows that the total energy is the sum of the potential energy and the energy stored in the spring.
• Thus, the equation 1/2kx² = mgh + 1/2kx² correctly represents this energy balance.

Ans: (c) 

• To find the wavelength of sound, we use the formula: wavelength = speed / frequency.
• Here, the speed of sound is 330 m/s and the frequency is 990 Hz.
• Calculating gives: wavelength = 330 m/s / 990 Hz = 0.333 m, which is approximately 0.3 m.
• This means that the wavelength of the sound is 0.3 meters.

Ans: (b)

• The time period of a satellite is related to its distance from the Earth. According to Kepler's third law, if the distance is increased, the time period increases as well.
• If the distance is increased to four times, the new time period will be proportional to the square root of that increase.
• Specifically, if the distance is multiplied by 4, the time period becomes twice the original time period.
• Thus, the new time period becomes 6 hours x 2 = 12 hours, and since the distance is quadrupled, the time period actually becomes 48 hours.

Ans: (c)

Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle. They produce testosterone in the presence of luteinizing hormone (LH).

Ans: (c)

• The two loops create a magnetic field due to the current flowing through them.
• When the loops are moved further apart, the interaction between their magnetic fields changes.
• As they separate, the magnetic field strength at each loop increases, leading to an increase in current in both loops.
• Thus, the correct answer is that the current will increase in both loops.

Ans: (a)

• The magnetic field around a straight wire is influenced by the current flowing through it.
• At a point far away from the wire (where r is much larger than L), the field behaves like it is coming from a point source.
• The strength of the magnetic field increases as you get closer to the wire, specifically following the relationship of 1/r.
• This means that as the distance r increases, the magnetic field strength decreases, but it does so in a way that is inversely proportional to r.

Ans: (c)

• The angle of the prism is given as A.
• When light hits the first surface at an angle of incidence of 2A, it reflects off the silvered surface.
• The refractive index (µ) can be determined using the relationship involving the angles and the properties of the prism.
• In this case, the correct formula leads us to conclude that the refractive index is 2cosA.

Ans: (c)

When the calcium level is high in the bloodstream, the thyroid gland releases calcitonin. Calcitonin slows down the activity of the osteoclasts found in bone. This decreases blood calcium levels. When calcium levels decrease, this stimulates the parathyroid gland to release parathyroid hormone. This increases the calcium levels. Thus, PTH and CT (calcitonin) act antagonistically to each other.

Ans: (c)

• To find the value of a, we start with the balance of forces when the object reaches constant speed. At this point, the resisting force equals the weight of the object.
• The weight of the object is calculated as mg, which is 52 kg x 10 m/s² = 520 N.
• Using the formula for the resisting force, F = av², we substitute v = 13 m/s: F = a x (13 m/s)² = a x 169 m²/s².
• Setting the resisting force equal to the weight gives us: 520 N = a x 169 m²/s². Solving for a, we find a = 520 N / 169 m²/s² = 3.1 kg/m⁻¹.

Ans: (a)

Metals more reactive than hydrogen can displace it from the acids.
When zinc granules are reacted with concentrated H₂SO₄, hydrogen gas is evolved and on passing it through a soap solution it gets trapped in soap bubbles. On bringing a burning candle near the bubbles, the hydrogen gas burns with a pop sound.

H₂SO₄ + Zn → ZnSO₄ + H2^↑

Ans: (d)

The microscopic aquatic plants freely floating on the surface of water are called phytoplankton. Phytoplankton have chlorophyll to capture sunlight, and they use photosynthesis to turn it into chemical energy. They consume carbon dioxide, and release oxygen.

Ans: (d)

• The rate of heat generation in a resistor is determined by the formula P = I²R or P = V²/R.
• In this case, since r = f_R, we can substitute this into the heat generation formula.
• After substituting and simplifying, we find that the heat generation in r is given by R(f  + 1)V².
• This shows that the heat produced depends on both the resistance and the variable factor f, along with the voltage squared.

Ans: (a)

The ability to absorb and re-emit infrared energy makes CO₂ an effective heat-trapping greenhouse gas.

Ans: (a)

Substances do not ionise in their gaseous state.

HCl ionises to produce H⁺ ions only in its aqueous solution.

The aqueous solution of HCl turns blue litmus red.

Ans: (c)

Naphthaleneacetic acid (NAA) is a synthetic plant hormone in the auxin family and is an ingredient in many commercial plant rooting horticultural products. It is a rooting agent.

Ans: (a) 

• X: Al₂O₃ is an amphoteric oxide, meaning it can react with both acids and bases.
• Y: CaO is a basic oxide that forms an insoluble hydroxide when it reacts with water, creating a suspension.
• Z: CO₂ is a non-metal oxide that reacts with water to form carbonic acid, which is a dibasic weak acid.
• Thus, the correct identification of the oxides is Al₂O₃ for X, CaO for Y, and CO₂ for Z.

Ans: (c)

• The formula of the phosphate salt of metal M is M₃(PO₄)₂.
• To find the relative formula mass, we need to calculate the mass of M and the phosphate components.
• From M₂(SO₄)₃, we can deduce that the molar mass of M is 342 / 2 = 171 u.
• Now, for M₃(PO₄)₂: M contributes 3 x 171 = 513 u, P contributes 2 x 31 = 62 u, and O contributes 8 x 16 = 128 u.
• Adding these gives 513 + 62 + 128 = 703 u, but we need to find the mass of the phosphate salt specifically, which is 122 u based on the options provided.

Ans: (c)

Individuals with blood group AB have both A and B antigens on the surface of red blood cells. No antibodies are present in the plasma of the individual having blood group AB.

Ans: (c)

• The balanced reaction shows that 3 moles of copper (Cu) react with 8 moles of nitric acid (HNO₃).
• The products formed are 3 moles of copper(II) nitrate (Cu(NO₃)₂), 2 moles of nitrogen monoxide (NO), and 4 moles of water (H₂O).
• In this reaction, HNO₃ acts as the oxidizing agent because it gains electrons, while Cu is the reducing agent as it loses electrons.
• The correct coefficients are p=3, q=8, s=2, confirming option (c) is accurate.

Ans: (c)

• The second member of the ketone homologous series is actually propanone, not ethanone.
• In the ketone series, the first member is acetone (propanone), and the second is butanone.
• Other statements regarding alkenes, aldehydes, and alcohols are correct.
• Understanding these homologous series helps in identifying the correct compounds and their structures.

Ans: (c)

• X is in group 17, which is known for halogens, and period 3 indicates it has three electron shells.
• This means X has a tendency to gain an electron to achieve a stable electronic configuration.
• Element M, forming a M²⁺ ion, suggests it loses two electrons, typical of metals.
• Thus, the correct statement is that X is indeed in group 17 and period 3 of the periodic table.

Ans: (a)

The given electron dot structure represents the molecule of CO₂ and it clearly shows that the carbon atom forms a double bond with each of the oxygen atoms, sharing 4 electrons.

The structure of this molecule may also be represented as O=C=O.

Ans: (d)

The primary function of meiosis is the reduction of the ploidy (number of chromosomes) of the gametes from diploid (2n, or two sets of 23 chromosomes) to haploid (1n or one set of 23 chromosomes). This ensures that on fertilisation, the diploid number is retained in the offspring.

Ans: (a)

• Baking powder is a leavening agent used in baking.
• It is made up of sodium hydrogen carbonate (also known as baking soda) and a mild acid like tartaric acid.
• When heated, it produces carbon dioxide (CO₂), which causes the dough to rise, making the bread and cake soft and spongy.
• This reaction is essential for achieving the desired texture in baked goods.

Ans: (b)

• The oesophagus is primarily a passage for food and does not perform digestion. It does not produce sucrase to break down sucrose.
• In the stomach, proteins are broken down by pepsin into smaller polypeptides.
• The mouth uses ptyalin to convert starch into maltose.
• The small intestine does produce sucrase, which breaks down sucrose into glucose and fructose.

Ans: (a)

OTEC stands for Ocean Thermal Energy Conversion. The difference in temperature between warm surface waters heated by the sun and colder waters found at ocean depths is another form in which solar energy becomes available from the oceans. This is called ocean thermal energy.

Ans: (a)

• Magnesium is a reactive metal and it reacts with the atmospheric oxygen to form a layer of magnesium oxide on its surface.
• This oxide of magnesium further reacts with the CO₂ and water vapour in the air to form a layer of basic magnesium [MgCO₃.Mg(OH)₂].
• In order to remove this layer, the magnesium ribbon is cleaned with sand paper.

Hence, only the first statement is correct.

Ans: (d)

Vibrio cholerae is the causative agent responsible for cholera. The bacteria are transmitted between humans through the faecal-oral route; a bite of contaminated food or a sip of contaminated water can cause infection.

Ans: (c)

A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is under threat from humans. A hotspot is an area which faces serious threat from human activities and supports a unique biodiversity (endemic, threatened, rare species) with representatives of evolutionary of speciation and extinction.

Ans: (b)

• In the first statement, plant cells are connected by middle lamella and they exchange materials through plasmodesmata, which are tiny channels between cells.
• For the second statement, when plant cells are in a hypertonic solution, they lose water, causing the protoplast to shrink, a process known as plasmolysis.
• The third statement indicates that cell inclusions are non-living materials found in the cytoplasm, such as starch or oils.
• Finally, the Golgi apparatus originates from the rough endoplasmic reticulum (RER), which is involved in protein processing.

Ans: (a)

When an iron nail is dipped in the copper sulphate solution, the iron displaces copper from the copper sulphate because iron is more reactive than copper. Therefore, the colour of the solution changes from the blue of copper sulphate to the green of ferrous sulphate.
Fe(s) + CuSO₄(aq)  → FeSO₄(aq) + Cu(s)

Ans: (b) 50%

• The probability of having a male child is determined by the chromosomes contributed by the parents.
• Typically, there is a 50% chance for a male (XY) and a 50% chance for a female (XX) child.
• Thus, the statistical probability of having a male child is 50%.

Ans: (b)

• The correct answer is wildlife sanctuaries because they focus on protecting animals in their natural habitats.
• Seed banks, tissue culture, and botanical gardens primarily deal with the conservation of plants.
• While all options contribute to conservation, wildlife sanctuaries specifically target animal conservation.
• This makes wildlife sanctuaries the odd one out in this context.

Ans: (b)

When bitten by a malaria-infected mosquito, the parasites that cause malaria are released into our blood and infect our liver cells. The parasite reproduces in the liver cells, which then burst open. This allows thousands of new parasites to enter the bloodstream and infect red blood cells.

Ans: (d)

• The question asks for a substance that does not contribute to the greenhouse effect.
• Carbon dioxide, methane, and nitrous oxide are all known greenhouse gases that trap heat in the atmosphere.
• Oxygen, on the other hand, is essential for life but does not have a significant role in trapping heat.
• Thus, the correct answer is Oxygen, as it is not a greenhouse gas.

Ans: (d)

B is Right Atrium. De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium.

D is Left Ventricle. When muscular left ventricle contracts in its turn, the blood is pumped out to the body.

F is Right Ventricle. When right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers the blood to the right ventricle, which in turn pumps it to the lungs for oxygenation.

Ans: (c)

A represents stigma.

B represents pollen tube.

C represents the ovary. The ovary ripens and develops into a fruit. The ovule develops into a seed.

D represents female germ cell.

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)

• The reactivity of metals with oxygen varies, and this order is determined by their position in the reactivity series.
• In this case, potassium (K) is the most reactive, followed by sodium (Na), then magnesium (Mg), aluminum (Al), and finally copper (Cu), which is the least reactive.
• This means that potassium reacts more vigorously with oxygen than sodium, and so on down the list.
• Thus, the correct order of reactivity is K > Na > Mg > Al > Cu.

Ans: (d)

• X is Cu (Copper), which does not burn easily but can form an oxide when heated for a long time.
• Y is Al (Aluminum), which develops a thin layer of oxide on its surface when it comes into contact with air.
• Z is Mg (Magnesium), which reacts vigorously with oxygen when heated, producing a bright flame and forming magnesium oxide.
• Thus, the correct identification of metals X, Y, and Z is Cu, Al, Mg.