SZF IOS 2025 previous year paper practice · PYQ-pattern set

SZF IOS 2025 PYQ-pattern questions

Showing 10 of the 20 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 · Motion

   A cyclist travels from point A to point B at a speed of 12 m/s and returns to point A at a speed of 8 m/s. What is the average speed for the entire journey?

   • A. 10 m/s
   • B. 9.6 m/s
   • C. 10.5 m/s
   • D. 8.5 m/s
   Answer and solution

   Answer: B

   Average speed = (2 × v₁ × v₂) / (v₁ + v₂) = (2 × 12 × 8) / (12 + 8) = 192 / 20 = 9.6 m/s.

2. Q2 · Light — Reflection and Refraction

   A ray of light is incident on a plane mirror at an angle of 35° to the mirror surface. What is the angle of reflection measured from the normal?

   • A. 35°
   • B. 55°
   • C. 70°
   • D. 90°
   Answer and solution

   Answer: B

   Angle of incidence from normal = 90° - 35° = 55°. By law of reflection, angle of reflection = 55°.

3. Q3 · Magnetic Effects of Current

   A current-carrying straight conductor is placed in a uniform magnetic field such that the current flows perpendicular to the direction of the magnetic field. If the current through the conductor is 3 A and the magnetic field strength is 0.4 T, what is the magnitude of the force per unit length acting on the conductor?

   • A. 0.6 N/m
   • B. 1.2 N/m
   • C. 0.8 N/m
   • D. 1.5 N/m
   Answer and solution

   Answer: B

   The force per unit length on a current-carrying conductor in a magnetic field is F/l = B × I. Here, F/l = 0.4 × 3 = 1.2 N/m.

4. Q4 · Structure of the Atom

   An element X has an atomic number 17 and mass number 35. How many neutrons are present in one atom of this element?

   • A. 17
   • B. 18
   • C. 35
   • D. 52
   Answer and solution

   Answer: B

   Number of neutrons = Mass number - Atomic number = 35 - 17 = 18 neutrons.

5. Q5 · Metals and Non-Metals

   A student places iron nails in copper sulphate solution and observes a reddish-brown coating on the nails after some time. Which property of metals is demonstrated in this experiment?

   • A. Malleability
   • B. Ductility
   • C. Reactivity
   • D. Conductivity
   Answer and solution

   Answer: C

   Iron is more reactive than copper, so it displaces copper from copper sulphate solution, forming a reddish-brown coating of copper on the nails, demonstrating the reactivity series of metals.

6. Q6 · Cell — Fundamental Unit of Life

   Which cell organelle is known as the 'powerhouse of the cell' because it produces energy in the form of ATP?

   • A. Ribosomes
   • B. Mitochondria
   • C. Golgi apparatus
   • D. Endoplasmic reticulum
   Answer and solution

   Answer: B

   Mitochondria are called the powerhouse of the cell as they carry out cellular respiration and produce energy in the form of ATP molecules.

7. Q7 · Improvement in Food Resources

   Which of the following is a rabi crop commonly grown in northern India during the winter season?

   • A. Rice
   • B. Wheat
   • C. Cotton
   • D. Groundnut
   Answer and solution

   Answer: B

   Wheat is a rabi crop sown in winter (October-December) and harvested in spring, while rice is a kharif crop grown in the monsoon season.

8. Q8 · Our Environment

   In a food chain, if 10,000 J of energy is available at the producer level, approximately how much energy will be available to secondary consumers?

   • A. 10 J
   • B. 100 J
   • C. 1,000 J
   • D. 5,000 J
   Answer and solution

   Answer: B

   According to the 10% law of energy transfer, only about 10% of energy passes to the next trophic level. From producers (10,000 J) to primary consumers (1,000 J) to secondary consumers (100 J).

9. Q9 · Scientific Reasoning

   A student observes that ice cubes placed in a glass of water gradually decrease in size. Which scientific principle best explains this observation?

   • A. Ice undergoes sublimation at room temperature
   • B. Ice melts by absorbing heat from its surroundings
   • C. Water evaporates faster than ice melts
   • D. Ice expands and breaks into smaller pieces
   Answer and solution

   Answer: B

   Ice melts when it absorbs heat energy from the surrounding water and air, changing from solid to liquid state through the process of melting.

10. Q10 · Data and Chart Interpretation

    A bar chart shows daily temperature readings: Monday 25°C, Tuesday 28°C, Wednesday 27°C, Thursday 30°C, Friday 26°C. On which day was the temperature highest?

    • A. Monday
    • B. Tuesday
    • C. Wednesday
    • D. Thursday
    Answer and solution

    Answer: D

    Thursday recorded 30°C, which is the highest temperature among all the days shown in the data.