Science Olympiad Previous Year Paper - 3 | Science Olympiad Class 9 PDF Download

Ans: (d)

• From the expression, P % Q indicates that P is the mother of Q.
• Next, Q + R shows that Q is the son of R, making R the father of Q.
• Then, R @ S means R is the father of S, so S is the child of R.
• Finally, S & T indicates that S is the husband of T, making P the mother-in-law of T.

Ans: (b)
The father of the boy's uncle is the grandfather of the boy and the daughter of the grandfather is the sister of the father.
So, the boy is the brother of the girl.

Ans: (d)

• First, replace the letters with their corresponding operations: 28 – 14 ÷ 2 × 7 + 24.
• Next, follow the order of operations: division and multiplication first, then addition and subtraction.
• Calculate 14 ÷ 2 = 7, then 7 × 7 = 49.
• Now, perform the operations from left to right: 28 – 49 + 24 = -21 + 24 = 3.

Ans: (d)
The line segment rotates through 90o and moves to the adjacent portion of the rhombus in an anti-clockwise direction in first, third, fifth, ... steps. The other symbol moves to the adjacent portion of the rhombus in an anti-clockwise direction and also gets replaced by a new symbol in second, fourth, sixth, ... steps.

Ans: (b)

• The sequence starts with DB and continues with ADB. The missing letters follow a pattern.
• After ADB, the next part is AD, which suggests the next letter should be C to maintain the sequence.
• Continuing this logic, the next letters should be DB and then A again, leading to the option CCBAC fitting perfectly.
• Thus, the correct answer is CCBAC, which matches the missing letters in the sequence.

Ans: (b)
Only in fig. (5), the arrowhead along the circumference of the circle indicates motion in the anti-clockwise direction.

Ans: (b)
The pattern is -1, x10 + 1, -1, x10 + 1, -1, x10 + 1, ...
So, missing term = 10 x 10 + 1 = 101

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

Ans: (b)

• The logical sequence starts with the Patient (1) who visits the Doctor (3).
• Next, the Doctor makes a Diagnosis (5) of the patient's condition.
• Following the diagnosis, the Treatment (4) is provided.
• Finally, the Patient (1) can Recover (2) after receiving the treatment.

Ans: (a)

• Sahil starts facing South and turns right, which means he is now facing West.
• He walks 20 m towards the West.
• After another right turn, he faces North and walks 30 m.
• Finally, he turns right again to face East and walks 60 m.
• To find the distance from the starting point, we can visualize his path: he moves 20 m West, then 30 m North, and finally 60 m East. This results in a net movement of 40 m East and 30 m North.
• Using the Pythagorean theorem, the distance from the starting point is calculated as sqrt((40)^2 + (30)^2) = 50 m.

Ans: (d)

• To find the total time taken, we can use the formula: v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration (which is -g here), and t is the time.
• Here, the initial velocity (u) is 25 m/s, the final velocity (v) is -90 m/s (downward), and g is 10 m/s².
• Rearranging the formula gives us: t = (v - u) / a. Plugging in the values: t = (90 - 25) / 10 = 6.5 s.
• However, since the stone goes up and then comes down, we need to consider the total time for both the upward and downward journey, which results in a total time of 11.5 s.

Ans: (a)
Atoms of different elements with same number of neutrons but different atomic and mass numbers are known as isotones.

Ans: (d)

• To find the force on the floor of the helicopter: The total weight of the crew and passengers is calculated as 500 kg × 10 m/s² = 5000 N. The helicopter's weight is 2000 kg × 10 m/s² = 20000 N. The total force is the weight plus the force due to acceleration: 20000 N + (2000 kg × 15 m/s²) = 20000 N + 30000 N = 50000 N. The force on the floor is 50000 N + 5000 N = 55000 N, which is 1.25 × 10⁴ N.
• The action of the rotor: The rotor pushes down on the air with a force equal to the total weight of the helicopter and the additional force due to acceleration, which is 6.25 × 10⁴ N downwards.
• The force from the air: According to Newton's third law, the air pushes back with an equal and opposite force of 6.25 × 10⁴ N upwards.
• Conclusion: All three statements are correct, making option (d) the right choice.

Ans: (b)
Mass by mass percent of solvent

Ans: (a)

• To find the velocity of waves in medium Y, we can use the formula: velocity = frequency × wavelength.
• First, convert the wavelengths to the same unit: 100 mm = 0.1 m and 0.25 cm = 0.0025 m.
• Calculate the frequency in medium X: frequency = velocity / wavelength = 80 m/s / 0.1 m = 800 Hz.
• Now, use this frequency to find the velocity in medium Y: velocity = frequency × wavelength = 800 Hz × 0.0025 m = 2 m/s.

Ans: (d)

• Sphere A's behavior indicates that it must have a charge that can attract the positively charged sphere B.
• If sphere A were neutral, it wouldn't attract sphere B.
• Since sphere B is positively charged, sphere A must be either negatively charged (which would attract it) or neutral (which would not repel it).
• Thus, the correct conclusion is that sphere A is either negatively charged or neutral.

Ans: (c)

• Pressure in a liquid is determined by the depth of the liquid and the density of the liquid, but it does not depend on the shape of the container. This means that regardless of how the container is shaped, the pressure at a specific depth remains the same.
• The nature of the liquid and the acceleration due to gravity do affect pressure, but the container's shape does not.
• Thus, the correct answer is that pressure at a point inside a liquid does not depend on the shape of the container.

Ans: (d)

• Statement 1 is false because reducing the initial velocity to half actually decreases the stopping distance by a factor of 4, not 2.
• Statement 2 is true as it correctly states that stopping distance is proportional to the square of the initial velocity.
• This means that if you halve the velocity, the stopping distance decreases by a factor of 4 (since (1/2)^2 = 1/4).
• Thus, the correct option is (d) where statement 1 is false and statement 2 is true.

Ans: (a)
The electrical impulses flow from the dendrites to the cell body and the axon. The axon transfers the signal through its dendrites onto the next cell.

Ans: (b)

• The mass of the substance deposited at the cathode is directly proportional to the quantity of electricity passed through the electrolyte, meaning that as more electricity flows, more substance is deposited.
• It is also directly proportional to the time electricity is passed, indicating that longer time results in more deposition.
• Thus, statements (ii) and (iii) are correct, while (i) and (iv) are incorrect.
• In summary, the correct answer is (b) because both statements (ii) and (iii) accurately describe the relationship.

Ans: (c)

• When an object floats, the weight of the liquid displaced equals the weight of the object.
• In water, if 1/4 of the volume is above water, then 3/4 of the volume is submerged, indicating the density of the object is 3/4 gm/cc.
• In the second liquid, if 1/2 of the volume is above, then 1/2 is submerged, meaning the density of the liquid can be calculated using the ratio of the submerged volumes.
• Using the principle of buoyancy, the density of the liquid is found to be 3/2 gm/cc.

Ans: (c)
Elements A and C have the same number of valence electrons. Hence, they show the same chemical properties

Ans: (d)

• The question asks for the increasing order of rigidity, which means we need to identify the substances from least rigid to most rigid.
• Hydrogen is a gas and has very low rigidity, followed by Petrol, which is a liquid, and finally, a Wooden block, which is solid and more rigid.
• In contrast, the other options do not follow this order correctly, as they mix different states of matter without proper comparison of rigidity.
• Thus, the correct answer is (d) because it accurately reflects the increasing rigidity from gas to liquid to solid.

Ans: (d)

• The residue formed by heating iron filings and sulfur is a new substance. It cannot be separated back into its original components using simple physical methods.
• Its properties are distinct from those of iron and sulfur. This means it behaves differently than either of the original materials.
• The composition of the residue is uniform throughout. This indicates that every part of the residue has the same makeup.
• However, the statement that its appearance is different but shows chemical properties of both iron and sulfur is incorrect. The residue does not exhibit the chemical properties of the original substances.

Ans: (c)

• To find the mass by volume percentage, we use the formula: (mass of solute / volume of solution) x 100.
• For option (a): (10 g / 50 mL) x 100 = 20%.
• For option (b): (25 g / 100 mL) x 100 = 25%.
• For option (c): (30 g / 50 mL) x 100 = 60%.
• For option (d): (60 g / 200 mL) x 100 = 30%.
• Comparing these percentages, 30 g of magnesium sulfate in 50 mL gives the highest mass by volume percentage of 60%.

Ans: (b)
When the apical meristem is removed, various hormones insides the plant triggers the growth of a new bud using the intercalary meristem.

Ans: (a)

• Statement I is true; the carbonate ion does indeed have a charge of –2.
• Statement II is false; the sulfide ion is actually divalent and carries a negative charge, not trivalent and positive.
• Statement III is true; argon is a monoatomic gas while oxygen is diatomic.
• Statement IV is false; the ammonium ion is positively charged, not negatively charged.
• Thus, the incorrect statements are II and IV, making option a the correct answer.

Ans: (a)
The plant cell wall is made up of cellulose and hemicellulose and the most common component of the plant cell wall is cellulose.

Ans: (a)
Kingdom Plantae is divided into different classes, orders and families based on the following characters.

• Presence or absence of well-differentiated cell body
• Presence or absence of conductive tissue
• Ability to bear seeds
• Naked seeds or enclosed seeds (fruit)

Ans: (b)
If the dispersed phase is liquid and the dispersion medium is gas, the colloid formed is a aerosol

Ans: (a)
An object can have zero velocity and still be accelerating simultaneously. For example, when an object is projected vertically up, at the highest point its speed becomes zero whereas it is accelerating downwards with g. An object can be at rest with respect to one object and can be in motion with respect to one object and can be in motion with respect to another object.

Ans: (c)

• Statement 1 is true because fire brigades do indeed pour water on fires to extinguish them.
• Statement 2 is false because water actually cools the combustible material to below its ignition temperature, not above it.
• Thus, the correct option is that Statement 1 is true but Statement 2 is false.
• This means that while the action of pouring water is correct, the explanation regarding temperature is incorrect.

Ans: (b)

• Plasma membrane is crucial for maintaining the cell's identity and structure.
• It is selectively permeable, allowing certain substances to pass while blocking others, but it is not completely impermeable.
• It also has junctions that help in holding cells together and provides protection.
• Thus, the statement that it is impermeable is incorrect, making option (b) the right answer.

Ans: (d)

• Phagocytosis is a process where cells engulf and digest extracellular particles.
• Statement I is correct as it describes the intake of particles.
• Statement II is also correct because phagocytosis serves both a nutritive and defensive function for the cell.
• Statement III is the incorrect one; microfilaments actually play a crucial role in the process.
• Statement IV is correct as it describes how the cell membrane extends around the particle.

Ans: (a)

• Xylem is a type of complex permanent tissue in plants responsible for the transport of water and nutrients from the roots to the rest of the plant.
• It consists of various cell types, including tracheids and vessel elements, which work together to perform this function.
• Other options like Parenchyma, Sclerenchyma, and Phloem serve different roles; for instance, Phloem is involved in transporting sugars.
• Thus, the correct answer is Xylem, as it is specifically classified as a complex permanent tissue.

Ans: (c)

• Statement 1 is correct because smooth muscle fibers are indeed long, spindle-shaped, tapering, and have a single nucleus.
• Statement 2 is incorrect as smooth muscle fibers do not have transverse striations; they are non-striated and are found in the walls of tubular organs.
• Thus, the correct choice is that Statement 1 is true while Statement 2 is false.
• This leads us to the conclusion that option (c) is the right answer.

Ans: (b)

• Clostridium botulinum is a bacterium that produces toxins and is harmful, making it unsuitable for organic farming.
• In contrast, Anabaena and Cyanobacteria are beneficial microorganisms that can enhance soil fertility.
• Neem leaves are also commonly used in organic farming for their natural pest-repelling properties.
• Thus, the correct answer is (b) because it is not safe or beneficial for organic practices.

Ans: (a)

• Combustion is a chemical reaction that involves the burning of a substance in the presence of oxygen, producing heat and light.
• In contrast, evaporation, melting, and freezing are physical changes, not chemical reactions.
• Understanding the difference between chemical and physical changes is crucial in chemistry.
• Thus, the correct answer is (a) Combustion, as it represents a true chemical reaction.

Ans: (d)
The husk of the coconut contains sclerenchyma cells. The gritty texture in guava is due to the presence of sclereids. Sclereids are reduced forms of sclerenchyma cells that are spherical.

Ans: (a)
Number of electrons in M²⁺ ion = 10
Number of electrons in neutral M ion = 12
In a neutral atom, number of electrons is equal to the number protons.
Mass number = Number of protons + Number of neutrons
= 12 + 12 = 24

Ans: (a)

• Kanha National Park is famous for its population of Barasingha, not the Great Indian Bustard.
• The Sundarbans is indeed known for the Royal Bengal Tiger.
• Desert National Park is recognized for the Chinkara, which is correct.
• Corbett National Park is well-known for its Tiger population.

Ans: (a)

• Ribosomes are present in both plant and animal cells.
• Vacuoles are found in both types of cells, but they are larger in plant cells.
• Mitochondria are also present in both plant and animal cells.
• Plastids, such as chloroplasts, are unique to plant cells.
• Lysosomes are typically found in animal cells, not in plant cells.

Ans: (c)

• Parathyroid gland plays a crucial role in maintaining the balance of calcium and phosphate in the body.
• It releases a hormone called parathyroid hormone (PTH) that increases calcium levels in the blood.
• This gland is located behind the thyroid gland in the neck and is essential for bone health.
• Without proper function of the parathyroid gland, the body can experience issues like weak bones or muscle spasms.

Ans: (d)
When a plant cell is placed in a hypertonic solution, the water inside the cell will come out and the cell will shrink and will get detached from the cell wall. Nevertheless, the cell wall will remain its structure, shape and rigidity.
When a plant cell is placed in a hypotonic solution, the water will enter into the cell and the cell will swell up. But the cell wall will exert pressure on the cell called the “turgor pressure” and will retain the original shape and structure of the cell.

Ans: (c)

• Biomagnification refers to the process where the concentration of nonbiodegradable substances increases as you move up the food chain.
• This happens because predators consume multiple prey, leading to a higher accumulation of these harmful compounds.
• As a result, organisms at the top of the food chain, like eagles or humans, can have much higher levels of toxins compared to those at the bottom.
• Understanding this concept is crucial for environmental protection and food safety.

Ans: (a)
The slope of velocity-time graph for C is greater than that for B. Hence, the acceleration of C is greater than that of A.

Ans: (a)
Cholera is an acute diarrhoeal infection caused by injecting food or water contaminated by Vibrio cholera.

Ans: (c)

• Animal cells are correctly identified as eukaryotic cells in the passage.
• The term prokaryotic refers to cells without a defined nucleus, which is accurately described.
• Robert Hooke is the correct person associated with the term ""cell,"" so option (a) is incorrect.
• Options (b) and (d) also misrepresent the definitions provided in the passage.

Ans: (a)

Ans: (b)
Step 1: Calculate the total height from which the man falls into the water
The man initially climbs to a height of 6 meters above the water surface and then jumps an additional 3 meters above the springboard. So, the total height (h) from which the man falls is:
h = 6 m + 3 m = 9 m
Step 2: Calculate the potential energy at the top of the jump
The potential energy (PE) of the man at the topmost point is given by the formula:
PE = m × g × h
where:
m = 55 kg (mass of the man)
g = 9.8 m/s² (acceleration due to gravity)
h = 9 m
Substitute the values:
PE = 55 × 9.8 × 9 = 4851 J
Step 3: Calculate the work done by the water in stopping the man
The resisting force by the water acts over a certain distance d, which we need to find. The work done by the water (which stops the man) is equal to the mechanical energy he had when he hit the water.
The work done by the water is given by:
W = F × d
where:
F = 1500 N (the resisting force exerted by the water)
d is the depth to which the man sinks in the water.
Since the work done by the water is equal to the man’s mechanical energy, we can set:
1500 × d = 4851
Solve for d:
d = 4851 ÷ 1500 = 3.23 m

Step 4: Conclusion
The depth to which the man sinks in the water is approximately 3.23 meters. This is closest to option B (3.3 m).
Thus, the correct answer is B. 3.3 m.