SZF IOS 2024 previous year paper practice · PYQ-pattern set

SZF IOS 2024 PYQ-pattern questions

Showing 10 of the 19 PYQ-pattern questions in this set — freshly worded in that year's pattern, not the original questions. Answers and solutions open under each question.

1. Q1 · Force and Laws of Motion

   A force of 15 N is applied on a body of mass 3 kg initially at rest. What will be the velocity of the body after 4 seconds?

   • A. 15 m/s
   • B. 20 m/s
   • C. 10 m/s
   • D. 12 m/s
   Answer and solution

   Answer: B

   Using F = ma, acceleration a = F/m = 15/3 = 5 m/s². Using v = u + at with u = 0, v = 0 + 5×4 = 20 m/s.

2. Q2 · Human Eye and Colourful World

   A person suffering from myopia can see clearly up to 1.5 m. What type of lens and approximate power is needed to correct this defect to see distant objects clearly?

   • A. Convex lens, +0.67 D
   • B. Concave lens, -0.67 D
   • C. Convex lens, +1.5 D
   • D. Concave lens, -1.5 D
   Answer and solution

   Answer: B

   Myopia is corrected using a concave lens. Power P = -1/f = -1/1.5 = -0.67 D approximately.

3. Q3 · Sources of Energy

   Which of the following is a non-renewable source of energy?

   • A. Wind energy
   • B. Solar energy
   • C. Natural gas
   • D. Tidal energy
   Answer and solution

   Answer: C

   Natural gas is a fossil fuel formed over millions of years and cannot be replenished in a short time, making it a non-renewable source of energy.

4. Q4 · Chemical Reactions and Equations

   When a magnesium ribbon is burnt in air, a white powder is formed. What type of chemical reaction is this?

   • A. Decomposition reaction
   • B. Combination reaction
   • C. Displacement reaction
   • D. Double displacement reaction
   Answer and solution

   Answer: B

   Magnesium combines with oxygen from air to form magnesium oxide (white powder): 2Mg + O₂ → 2MgO. This is a combination reaction where two substances combine to form a single product.

5. Q5 · Carbon and its Compounds

   Which of the following is a saturated hydrocarbon with the molecular formula C₃H₈?

   • A. Propene
   • B. Propane
   • C. Propyne
   • D. Butane
   Answer and solution

   Answer: B

   Propane (C₃H₈) is a saturated hydrocarbon with only single bonds between carbon atoms, following the alkane general formula CₙH₂ₙ₊₂.

6. Q6 · Why Do We Fall Ill

   Which of the following diseases is caused by bacteria?

   • A. Typhoid
   • B. Malaria
   • C. Chickenpox
   • D. Dengue
   Answer and solution

   Answer: A

   Typhoid is caused by the bacterium Salmonella typhi, while malaria is caused by a protozoan, and chickenpox and dengue are viral diseases.

7. Q7 · Life Processes

   During aerobic respiration in mitochondria, glucose is completely oxidized. What is the net gain of ATP molecules produced per molecule of glucose?

   • A. 2 ATP
   • B. 8 ATP
   • C. 36-38 ATP
   • D. 100 ATP
   Answer and solution

   Answer: C

   Complete aerobic respiration of one glucose molecule yields approximately 36-38 ATP molecules through glycolysis, Krebs cycle, and electron transport chain.

8. Q8 · Data and Chart Interpretation

   The table shows plant growth (in cm) over 4 weeks under different light conditions: Condition | Week 1 | Week 2 | Week 3 | Week 4 Full Sun | 3 | 6 | 10 | 15 Partial | 2 | 4 | 6 | 8 Shade | 1 | 2 | 3 | 4 Which conclusion is most accurate based on this data?

   • A. All plants grow at the same rate regardless of light
   • B. Full sun exposure results in the fastest growth rate
   • C. Shade provides optimal conditions for plant growth
   • D. Partial light doubles plant height every week
   Answer and solution

   Answer: B

   Plants in full sun show the greatest total growth (15 cm) and the highest weekly increases, indicating that maximum light exposure produces the fastest growth rate.

9. Q9 · Contemporary Science

   Scientists recently developed a new biodegradable plastic made from algae that decomposes within 6 months. Which environmental problem does this innovation primarily address?

   • A. Air pollution from vehicle emissions
   • B. Persistent plastic waste accumulation
   • C. Depletion of the ozone layer
   • D. Acid rain formation
   Answer and solution

   Answer: B

   Biodegradable plastic that decomposes quickly directly addresses the critical problem of long-lasting plastic waste that persists in landfills and oceans for hundreds of years.

10. Q10 · Sound

    A sound wave travels through air at 340 m/s and has a wavelength of 0.68 m. What is the frequency of this sound wave?

    • A. 200 Hz
    • B. 500 Hz
    • C. 680 Hz
    • D. 340 Hz
    Answer and solution

    Answer: B

    Using the formula v = fλ, we get f = v/λ = 340/0.68 = 500 Hz.