Science Olympiad Model Test Paper - 2 | Olympiad Preparation for Class 10 PDF Download

Ans: (a)
Wife of Aashi’s husband - Aashi; Brother of daughter - Son.
So, the boy on the stage is Aashi’s son.

Ans: (d)
Person’s father = Only son of woman’s daughter’s grandfather’s husband’s = Woman’s husband.
So, he is the son of the woman.

Ans: (d)

• The input line consists of words and numbers that are rearranged in a specific order.
• In Step III, the arrangement shows "efficient 84 mother my very 46 32 70".
• To determine the original input, we need to analyze the pattern of rearrangement.
• However, the exact original input cannot be definitively concluded from the given Step III.
• Thus, the answer is that it "Can't be determined".

Ans: (d)

• Understanding relationships: P is the son of Q, making Q his parent.
• Q and R are sisters, meaning they share the same parents.
• T is the mother of R, which makes T the mother of Q as well, since they are sisters.
• S is T's son, which means S is a brother to R and Q, making S the maternal uncle of P.

Ans: (c)
This sequence 2, 15, 4, 12, 6, 7, ?, ? is a combination of two series :

1st: 2, 4, 6, ? and 2nd: 15, 12, 7, ?

1st consists of consecutive even numbers.

So, missing term of 1st sequence = 8.

Pattern of 2nd sequence is -3, -5, ...

So, missing term of 2nd sequence = 7 - 7 = 0.

Ans: (d

She is in the south-east direction from the starting point.

Ans: (a)

∴ Number 3 appears on the same face.

Hence, 2 is opposite to number 6 and 5 is opposite to number 1.

Ans: (a)

The relation between EFRT and GJXB is as follows:-

E + 2 = G

F + 4 = J

R + 6 = X

T + 8 = B

In the same way, DNSL : FRYT

D + 2 = F

N + 4 = R

S + 6 = Y

L + 8 = T

Ans: (c)

• The word 'beautiful' appears in the phrases 'birds are beautiful' and 'sky is beautiful'.
• In the code, 'birds are beautiful' translates to 're pa si', and 'sky is beautiful' translates to 'so ve si'.
• From 'sky is beautiful', we see that 'si' is the common code for 'beautiful'.
• Thus, the correct code for 'beautiful' is 'si'.

Ans: (a)

• From the clues, we know that Q takes the exam on Monday in the 1st shift.
• S takes the exam on Friday in the 2nd shift.
• Since R takes the exam just before S, R must take the exam on Thursday.
• That means T takes the exam on Wednesday in the last shift.
• Thus, P must take the exam on Tuesday in the 3rd shift.

Ans: (b)

• The problem states that mass P takes twice the time to stop compared to mass Q.
• However, P only covers 41% of the distance that Q does before stopping.
• Using the relationship between distance, time, and velocity, we can derive that the initial velocities of P and Q are in the ratio of 1:8.
• This means that for every 1 unit of velocity of P, Q has 8 units of velocity initially.

Ans: (b)

The only difference between an AC generator and a DC generator is that a split-ring commutator is used in DC generator, whereas two slip rings are used in AC generator.

Ans: (c)

When the charge particle is moving parallel to the magnetic field, force exerted by the magnetic field on it will be zero. The force exerted by the electric field on the electron will be opposite to the direction of the electric field.

Hence, if the electron is moving parallel to the electric field and the magnetic field, the electron will move in the same straight direction with decreasing speed.

Ans: (c)

• Statement 1 is true because if the gravitational constant G were to decrease, the gravitational pull of the Earth would weaken, potentially allowing it to drift away from the solar system.
• Statement 2 is false because a decrease in G would actually mean that the gravitational force becomes weaker, not stronger.
• Thus, the correct option is that statement 1 is true while statement 2 is false.

Ans: (a)

Metals that are more reactive can displace the less reactive metals from their salt solution.

Reactivity series: K, Na, Ca, Mg, Al, Zn, Fe, Sn, Pb, [H], Cu, Hg, Ag, Au, Pt

The observation in the given activity that a grey deposit is seen in both the beakers indicates that metal 'X' is more reactive than both silver (Ag) and zinc (Zn) and can displace these metals from their salt solutions.

'X' is aluminium (Al).

Ans: (b)

We know, potential difference, V = W/Q

Here, potential difference, V = 128 – 118 = 10 volts

Work done, W = ?

Charge on the He²⁺ ion = 2 × 1.6 × 10^-19 = 3.2 × 10^-19 C

Hence, work done, W = VQ = 10 × 3.2 × 10^-19 = 32 × 10^-19 J

Ans: (a)

In order to survive, there will be genetic variation in the allele frequency. As an adaptive response for camouflage, the frequency of white allele will increase. The rabbits with white fur will be better camouflaged than the rabbits with brown fur. Hence, the frequency of white allele will increase.

Ans: (c)

• Statement 1 is incorrect because loudness is actually determined by the amplitude of the sound wave, not its frequency.
• Statement 2 is correct as it accurately describes that the amplitude of a sound wave is related to how intensely an object vibrates.
• Thus, the correct option is that Statement 1 is false and Statement 2 is true.

Ans: (d)

From the figure we can conclude that the image formed is erect and virtual. As the object moves from O to O', the image approaches the mirror from I to I'.

Size of the image becomes less and the distance travelled by the image is more than the distance travelled by the object in the same time, so the speed of the image is more than the speed of the object.

Ans: (c)

• To find the efficiency, we first calculate the input power using the formula: Input Power = Output Power + Power Loss.
• The output power is given as 20kW. The power loss can be calculated using the formula: Power Loss = I²R, where R is the resistance (0.5Ω).
• First, we find the current (I) using the formula: P = VI, where P is the output power (20,000W) and V is the voltage (220V). This gives us I = 20,000W / 220V = 90.91A.
• Now, calculate the power loss: Power Loss = (90.91A)² x 0.5Ω = 4131.5W or approximately 4.13kW.
• Now, Input Power = 20kW + 4.13kW = 24.13kW. Finally, efficiency = (Output Power / Input Power) * 100 = (20kW / 24.13kW) x 100 = 82.9%.

Ans: (d)

• Hazardous waste is waste that poses a substantial and potential threat to public health or the environment. In the United States, the treatment, storage, and disposal of hazardous waste are regulated under the Resource Conservation and Recovery Act (RCRA). The most common examples of hazardous waste found within the homes include paints, batteries, solvents, cleaning agents and pesticides.
• Among the listed substance, chlorine bleach is a chemical which is hazardrous, if not disposed properly.

Ans: (b)

Synaptic transmission relies on the availability of the neurotransmitter; the release of the neurotransmitter by exocytosis; the binding of the postsynaptic receptor by the neurotransmitter; the functional response of the postsynaptic cell; and the subsequent removal or deactivation of the neurotransmitter.

Ans: (c)

The resistance of a wire is given by:

Ans: (b)

• To find out which substance has the least number of atoms, we need to calculate the number of moles for each substance using the formula: moles = mass/atomic mass.
• For Sodium (Na): 10 g / 23 u = 0.434 moles, which equals approximately 0.434 x 6.022 x 10²³ atoms = 2.61 x 10²³ atoms.
• For Methane (CH4): 10 g / (12 + 4x1) = 10 g / 16 u = 0.625 moles, which equals approximately 0.625 x 6.022 x 10²³ atoms = 3.76 x 10^23 atoms.
• For Hydrogen fluoride (HF): 10 g / (1 + 19) = 10 g / 20 u = 0.5 moles, which equals approximately 0.5 x 6.022 x 10²³ atoms = 3.01 x 10²³ atoms.
• For Carbon (C): 10 g / 12 u = 0.833 moles, which equals approximately 0.833 x 6.022 x 10²³ atoms = 5.01 x 10²³ atoms.
• Among these calculations, Sodium has the least number of atoms at approximately 2.61 x 10²³ atoms.

Ans: (a)

Apical meristem is present on root apex, stem apex, leaf buds and flower buds. They are responsible for growth in length, i.e. primary growth.

Ans: (c)

Phagocytosis is an energy requiring process. The mitochondria is responsible for the production of ATP. Hence, high number of mitochondria gives enough energy for the process.

Ans: (b) 

• In option (b), the metallic character is listed as Na < Mg < Al < Si, which is incorrect because aluminum (Al) is more metallic than silicon (Si).
• In contrast, the other options correctly represent the trends in atomic radii, acidic nature, and non-metallic character.
• Thus, option (b) is the only one that does not follow the correct order.
• The question asks for the incorrect order of a property.

Ans: (c)

• Isobars are atoms with the same mass number but different atomic numbers. In this case, P (1737) and S (1937) are isobars.
• Isotopes are atoms of the same element with different mass numbers. Here, P (1737) and Q (1836) are isotopes.
• Thus, the correct pair of isobars and isotopes is P and S.
• Option (c) correctly identifies this pair.

Ans: (c)

• The correct answer is (c) because CH₃COOK (potassium acetate) is a salt derived from a weak acid (acetic acid) and a strong base (potassium hydroxide). This results in a solution that is basic, hence the pH is greater than 7.
• In contrast, CaSO₄ does not significantly affect the pH when dissolved, and K₂CO3 is a basic salt, so its pH is also greater than 7, not equal to 7.
• Lastly, CH₃COONa (sodium acetate) also results in a basic solution, not an acidic one.

Ans: (a)

A convex lens can be used as a simple magnifier if the object is placed between focal and optical centre.

Magnification of the magnifier, m  = D/f; where D is the least distance of distinct vision.

Ans: (d)

Synapse is the junction between two neurons. In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron.

Ans: (a)

• To find the number of atoms in 0.25 moles of MgSO₄, we first note that each formula unit contains 1 Mg, 1 S, and 4 O atoms.
• Calculating the total atoms: For Mg, it is 0.25 moles × 6.022×10²³ = 1.505×10²³ atoms.
• For S, it is also 0.25 moles × 6.022×10²³ = 1.505×10²³ atoms.
• For O, it is 0.25 moles × 4 × 6.022×10²³ = 6.023×10²³ atoms.
• Thus, the number of atoms of Mg, S, and O are 1.505×10²³, 1.505×10²³, and 6.023×10²³, respectively.

Ans: (c)

In some organisms, the unfertilised egg can develop into a new individual. This type of development without fertilisation is called parthenogenesis. Examples: Rotifers, drones of honeybees, etc.

Ans: (a)

It is due to refraction of the light. Refraction is the phenomenon in which there is a change in the path of the light with change in the medium.

In the given case, the ray of the light travels from denser medium to rarer medium. It bends away from the normal, so the coin will appear to be raised.

Ans: (b)

Centromere is the region of a chromosome to which the microtubules of the spindle attach, via the kinetochore, during cell division. During prophase, the spindle also begins to form as the two pairs of centrioles move to opposite poles and microtubules begin to polymerise from the duplicated centrosome.

Ans: (a)

• Mendel's Law of Dominance explains that when two different traits are crossed, only one trait will be visible in the first generation (F₁).
• This means that the dominant trait overshadows the recessive one, making it appear as if the recessive trait is not present.
• In simple terms, if you have a tall plant and a short plant, the offspring will only show the tall trait.
• This principle is fundamental in understanding how traits are inherited in genetics.

Ans: (a)

• Green color of seed is a trait that Mendel found to be recessive, meaning it only appears when both alleles are for green seeds.
• The other traits, such as tall plant size, violet flower color, and inflated pod shape, are dominant traits.
• This means that if a plant has at least one dominant allele for these traits, they will be expressed.
• In contrast, the recessive trait will only show up if the plant has two recessive alleles.

Ans: (d)

The disease that can be inferred from the given data is diabetes.
Diabetes is caused due to insufficient production of insulin by the beta cells of the pancreas.

Ans: (d)

• The ozone layer protects us from harmful ultraviolet (UV) radiation from the sun.
• When the ozone layer is depleted, it can lead to serious health issues such as cancer and cataracts.
• Additionally, it can weaken the body's immune system, making it harder to fight off diseases.
• It can also affect developing embryos, leading to increased mortality rates.
• Thus, all the listed effects (i, ii, iii, and iv) are caused by ozone depletion.

Ans: (a)

All sour substances like curds and pickles contain acids, and acids react with metals.

Such food if kept in brass or copper vessels will cause chemical reactions, which are likely to yield toxic products

Ans: (a)

• The Bhakra Dam is located on the Satluj river, making this pairing correct.
• The Tehri Dam is actually on the Bhagirathi river, not Tawa.
• The Sardar Sarovar Dam is built on the Narmada river, not Kaveri.
• The Mettur Dam is situated on the Kaveri river, not Narmada.

Ans: (c)

• The seminal vesicle plays a crucial role in the male reproductive system.
• It primarily functions to provide energy to sperm, which is essential for their motility.
• Additionally, it helps in making the transport of sperm easier within the female reproductive tract.
• However, it does not secrete follicle-stimulating hormone, which is produced by the pituitary gland.

Ans: (b)

The salivary glands in mammals are exocrine glands, glands with ducts, that produce saliva. The 3 types of salivary glands are parotid, submandibular and sublingual glands.

Ans: (c)

• The rough endoplasmic reticulum (RER) is characterized by the presence of ribosomes on its surface, which is why it is termed "rough".
• Statement (i) is correct as RER does consist of tubules and vesicles.
• Statement (iv) is incorrect because the products synthesized in the RER do indeed pass into the lumen for further processing.
• Thus, the incorrect pair of differences is (i) and (iv), making option (c) the right choice.

Ans: (b)

• The correct answer is runoff water from fields, roads, etc. because it comes from multiple sources and is not easily traceable to a single point.
• This type of pollution occurs when rainwater or melting snow washes pollutants off surfaces and into water bodies.
• In contrast, factories and oil wells are considered point sources because they discharge pollutants from a specific location.
• Understanding the difference between point and non-point sources is crucial for effective water pollution management.

Ans: (d)

• The heart's function is crucial, and the paragraph explains the heartbeat process.
• The term cardiac output is correctly used to describe the events of a heartbeat.
• Diastole refers to the heart's relaxation, while systole refers to contraction; they are correctly defined.
• The aorta and pulmonary artery are correctly identified in their roles in blood circulation.

Ans: (c)
Considering the image of the point A,
u = -40 cm, f = -10 cm
Using mirror formula:

Considering the image of the point B,

Length of the image = v_B - v_A = 15 - 13.3 = 1.7 cm

Ans: (a)

Soaps are sodium or potassium salts of higher fatty acids. They are prepared by heating vegetable oils (esters of higher fatty acids) with alkalies (NaOH or KOH).

Vegetable oils + NaOH  → Soap + Glycerol

This reaction is called saponification.

Once soap is formed, NaCl is added to help in precipitation of the soap.

Hence, both statements I and II are correct, but statement II is not the correct reason for I.

Ans: (b)

To determine the focal length of a concave mirror by obtaining the image of distant object, place the screen in front of the mirror and the concave mirror should be fixed in the vertical plane.

The base of the concave mirror stand and the screen should be parallel to the metre scale.

Ans: (b)

• Statement I is incorrect because size is not solely determined by the number of electrons; it also depends on the number of protons and the overall atomic structure.
• Statement II is correct as metals in group 13 typically have a valency of 3.
• Statement III is incorrect because R and W are not noble gases; noble gases are elements like helium, neon, and argon.
• Thus, the only incorrect statement is I, making option (b) the correct answer.