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GOPAL JI MEMORIAL SCHOOL

Reoti, Ballia (U.P.) · Affiliated to CBSE · www.gjms.edu.in
SAMPLE QUESTION PAPER · Session 2026-27
SCIENCE (Advanced · Optional) — Class IX
Time Allowed: 1 HourMaximum Marks: 25
General Instructions:
  1. This is the optional Advanced (enrichment) paper in Science. Attempting it is voluntary and its marks are not added to the aggregate; a candidate scoring 50% or more earns a distinction remark on the marksheet.
  2. The paper contains 13 questions in three sections. All questions are compulsory. There is no internal-assessment component.
  3. Every question is a Higher-Order Thinking Skills (HOTS) question drawn only from the Class IX Advanced enrichment content (10 chapters).
  4. Section A has 5 objective/very-short questions of 1 mark each. Section B has 4 questions of 2 marks each. Section C has 4 questions of 3 marks each.
  5. Internal choice (OR) is provided in some questions; attempt any one of the choices.
  6. Use of a non-programmable calculator is permitted. Take g = 10 m s⁻² unless otherwise stated. Show all working and give final answers with correct SI units.

SECTION A — Objective / Very Short Answer (HOTS) 5 × 1 = 5 marks

1.1 A student writes the speed of light as 3 × 108 m s⁻¹ and claims it "has infinite significant figures because it is a constant of nature". Give the number of significant figures actually shown in this written value, and state whether the student's reasoning is correct.
2.1 Two forces of 3 N and 4 N act on a point. Without any right-angle assumption, state the maximum and minimum possible magnitudes of their resultant.
3.1 Assertion (A): In the hydrogen line (emission) spectrum only certain discrete colours appear, not a continuous rainbow.
Reason (R): The electron in a hydrogen atom can occupy only fixed energy levels.
Choose: (a) Both A and R true, R correct explanation of A; (b) Both true, R not the correct explanation; (c) A true, R false; (d) A false, R true.
4.1 A microscope has a limit of resolution of 200 nm. Two dots are drawn 150 nm apart. State whether this microscope can show them as two separate dots, and name the single instrument property (not magnification) that decides this.
5.1 Curd-setting from milk and modern insulin production both use micro-organisms. Name the type of biotechnology (traditional or modern) used in each case.

SECTION B — Short Answer (HOTS) 4 × 2 = 8 marks

6.2 A spanner of length 25 cm is used to loosen a nut. A student applies a force of 40 N perpendicular to the spanner at its end.
  1. Calculate the torque (moment of force) produced about the nut. (1)
  2. If the same 40 N is applied at 30° to the spanner instead of 90°, will the torque increase, decrease or stay the same? Justify in one line. (1)
7.2 Convert a density of 2.7 g cm⁻³ (density of aluminium) into kg m⁻³, showing the unit-conversion factors used.
OR
The escape-related quantity "orbital speed" of a satellite is given as 7.9 km s⁻¹. Express this speed in m s⁻¹ and then estimate, to one significant figure, how many kilometres it travels in 1 minute.
8.2 Draw the Lewis (electron-dot) structure of the nitrogen molecule (N₂, atomic number 7) and use it to explain why N₂ is very unreactive at room temperature.
9.2 A green leaf pigment extract is spotted on chromatography paper and a solvent is allowed to rise.
  1. State what you would observe that proves the extract is a mixture. (1)
  2. Two pigments X and Y separate; X rises higher than Y. Which pigment is more soluble in the moving solvent, and why? (1)

SECTION C — Long Answer (HOTS) 4 × 3 = 12 marks

10.3 A car starts from rest and accelerates uniformly at 2 m s⁻² along a straight road.
  1. Using the equation of motion, find the distance it covers during the 5th second of its motion (i.e. the "nth-second" distance). (2)
  2. Explain in one line why this "distance in the 5th second" is larger than the distance covered in the 1st second, even though the acceleration is the same. (1)
11.3 A spring of force constant k = 200 N m⁻¹ is compressed by 10 cm and used to launch a small block of mass 0.5 kg on a smooth horizontal floor.
  1. Calculate the elastic potential energy stored in the compressed spring. (1½)
  2. Assuming all this energy is converted to kinetic energy, find the launch speed of the block. State which principle you used and whether the spring force is conservative or non-conservative. (1½)
OR
A 2 kg box is dragged 5 m along a rough floor at constant speed by a horizontal force of 8 N.
  1. Calculate the work done against friction. (1½)
  2. The box returns to its start by the same path; the total work done by friction over the round trip is not zero. Use this fact to explain why friction is called a non-conservative force. (1½)
12.3 Read the passage and answer.
Rutherford fired positively-charged α-particles at a very thin gold foil. Most passed straight through, a few were deflected through large angles, and about 1 in 20 000 bounced almost straight back. Later, Bohr proposed that electrons revolve around the nucleus only in certain "allowed" orbits and do not radiate energy while in them — an idea that successfully explained the hydrogen spectrum but could not explain the spectra of larger atoms.
  1. What did the rare large-angle bounce-back of α-particles tell Rutherford about the atom? (1)
  2. Classical physics predicted the revolving electron should spiral into the nucleus. State how Bohr's postulate avoided this. (1)
  3. State one limitation of the Bohr model mentioned or implied in the passage. (1)
13.3 Modern biotechnology often grows genetically-engineered bacteria in a large steel bioreactor to manufacture a medicine such as insulin.
  1. State one condition (other than food supply) that must be carefully controlled inside a bioreactor, and why. (1)
  2. Give one advantage of making human insulin this way rather than extracting it from animals. (1)
  3. State one ethical concern that society raises about modern genetic biotechnology. (1)
— END OF PAPER —
MARKING SCHEMEfor teachers

SECTION A — 1 mark each

1. The written value 3 × 10⁸ shows only 1 significant figure (the digit 3). (½) The student's reasoning is incorrect: significant figures depend on how a value is written/measured, not on whether the quantity is a constant; written as 3.00 × 10⁸ it would show 3 sig. figs. (½)
2. Resultant is maximum when the forces are parallel (same direction): 3 + 4 = 7 N. (½) Resultant is minimum when they are antiparallel (opposite): 4 − 3 = 1 N. (½)
3. Correct option: (a) — Both A and R are true and R is the correct explanation of A. Discrete energy levels ⇒ only fixed energy-difference photons ⇒ discrete spectral lines. (1)
4. No, the microscope cannot show them as two separate dots: the two dots lie 150 nm apart, which is closer than the 200 nm limit of resolution, so they merge into one blur. (½) The deciding property is the resolving power / limit of resolution (not magnification). (½)
5. Curd from milk → traditional biotechnology. (½) Modern insulin production (using genetically-engineered microbes) → modern biotechnology. (½)

SECTION B — 2 marks each

6. (a) Torque τ = force × perpendicular distance = 40 N × 0.25 m = 10 N m. (1)
(b) The torque will decrease, because only the perpendicular component (F sin30° = 40 × 0.5 = 20 N) is effective, giving τ = 20 × 0.25 = 5 N m < 10 N m; a force along the spanner produces no turning effect. (1)
7. 2.7 g cm⁻³ × (1 kg / 1000 g) × (100 cm / 1 m)³ = 2.7 × (1/1000) × 10⁶ kg m⁻³ (1) = 2.7 × 10³ = 2700 kg m⁻³. (1)
OR — 7.9 km s⁻¹ = 7.9 × 1000 = 7900 m s⁻¹. (1) In 1 minute (60 s) distance ≈ 7.9 × 60 = 474 ≈ ~500 km (to 1 significant figure). (1)
8. N (Z = 7) has 5 valence electrons; two N atoms share three pairs forming a triple bond, so each attains an octet: :N≡N: (a triple bond drawn as three shared pairs, with one lone pair on each N). (1) The N≡N triple bond is very strong (high bond energy), so a large amount of energy is needed to break it; hence N₂ is chemically very unreactive at room temperature. (1)
9. (a) The single spot separates into two (or more) differently-coloured spots/bands at different heights, proving more than one component is present ⇒ a mixture. (1)
(b) Pigment X is more soluble in the moving solvent, because a component more soluble in (and less strongly held than) the stationary phase is carried further and rises higher up the paper. (1)

SECTION C — 3 marks each

10. (a) Distance in nth second: sn = u + (a/2)(2n − 1), with u = 0, a = 2, n = 5.
s₅ = 0 + (2/2)(2×5 − 1) = 1 × (10 − 1) = 9 m. (2)
(b) The body speeds up continuously, so it is moving faster during the 5th second than during the 1st second; greater speed ⇒ greater distance covered in that (equal) one-second interval. (1)
11. (a) Elastic PE = ½ k x² = ½ × 200 × (0.10)² = ½ × 200 × 0.01 = 1 J. (1½)
(b) By conservation of energy, KE = ½ m v² = 1 J ⇒ v² = 2×1 / 0.5 = 4 ⇒ v = 2 m s⁻¹. The spring force is a conservative force (stored PE is fully recoverable). (1½)
OR — (a) At constant speed the applied force balances friction, so friction = 8 N; work against friction = F × d = 8 × 5 = 40 J. (1½)
(b) Friction always opposes motion, so on the return trip it again does negative work; over the closed round-trip path the total work is −80 J ≠ 0. A force whose work over a closed path is non-zero (energy is lost as heat, not recovered) is called non-conservative. (1½)
12. (a) The rare bounce-back showed that the atom's positive charge and almost all its mass are concentrated in a very small, dense central nucleus; most of the atom is empty space. (1)
(b) Bohr postulated that electrons revolve only in certain allowed (stationary) orbits in which they do not radiate energy, so they do not lose energy and do not spiral into the nucleus. (1)
(c) The Bohr model could not explain the spectra of atoms larger/heavier than hydrogen (multi-electron atoms). (1) (Accept: cannot explain fine spectral splitting / does not fit the quantum-mechanical picture.)
13. (a) Any one, with reason: temperature (kept optimal so the microbes/enzymes stay active and are not killed) / pH (kept in the microbe's tolerance range) / oxygen supply & stirring / sterility (to keep out contaminating microbes). (1)
(b) Human insulin made by engineered microbes is identical to human insulin, so it causes fewer allergic reactions, and can be produced in large, pure, reliable, animal-free quantities. (1)
(c) Any one valid concern: safety/long-term effects of releasing genetically-modified organisms, ethics of altering genes, unequal access/high cost, or possible misuse. (1)