Class 6 NSO Practice Paper with Answers & Solutions
Download free Class 6 NSO (National Science Olympiad) practice paper with complete solutions and explanations. Master logical reasoning and science concepts with expert-curated questions.
SECTION A: LOGICAL REASONING (Questions 1–5)
1. While going to office, P meets Q, who is related to P. P has a son R, who is married to T. T is the daughter of Q. T has a daughter A. How is P related to A?
A. Father-in-law
B. Grandfather / Grandmother
C. Uncle
D. Brother
2. Select the letter-number pair from the options to continue the series: D/1, ?, P/16, Y/25.
A. G/4
B. I/9
C. H/8
D. J/10
3. If B is coded as 4, F as 8, M as 15, and NEWS is coded as 4761, how is the word ‘TEACH’ coded following the same logic?
A. 63251
B. 52314
C. 73251
D. 84261
4. If ‘+’ stands for multiplication, ‘x’ stands for division, ‘-‘ stands for addition, and ‘÷’ stands for subtraction, what is the value of: 20 – 8 x 4 ÷ 3 + 2?
A. 16
B. 19
C. 41
D. 18
5. Shreya is facing West. She turns 225° in an anti-clockwise direction and then 135° in a clockwise direction. In which direction is she facing now?
A. East
B. South-East
C. South-West
D. South
SECTION B: SCIENCE (Questions 6–15)
6. A card with the word ‘BULB’ written on it is placed in front of a plane mirror. What is the correct laterally inverted image seen in the mirror?
A. BULB
B. ᙠ⅃Uᙠ
C. ᙠULᙠ
D. BLUB
7. Three magnets X, Y, and Z were dipped one by one in a heap of iron filings. Magnet X picked up maximum filings at both ends, Y picked up moderate, and Z picked up the least. What is the correct order of magnetic strength?
A. X < Y < Z
B. X = Y = Z
C. X > Y > Z
D. X < Y > Z
8. Consider the motion of the tip of the minute hand of a clock over the duration of exactly one hour. Which of the following statements is TRUE?
A. The total distance covered is zero.
B. The displacement is zero.
C. The average speed is zero.
D. None of these.
9. Which of the following methods is the correct step to demagnetise a permanent bar magnet using heating?
A. Heat the magnet red hot and let it cool in the East-West direction.
B. Heat the magnet red hot and let it cool in the North-South direction.
C. Heat the magnet in boiling water and cool in North-South direction.
D. Place it in a freezer immediately after heating.
10. Refer to the classification of fibres: Fiber X is obtained from the stem of a plant (e.g. Jute/Flax), and Fiber Y is obtained from animal cocoon without harming the organism during shearing or processing (e.g. Wool/Silk). Which pair is correctly matched?
A. X – Flax, Y – Silk
B. X – Cotton, Y – Silk
C. X – Flax, Y – Wool
D. X – Jute, Y – Wool
11. Which joint is present between the thigh bone (femur) and the shin bone (tibia) in the human skeleton?
A. Pivot joint
B. Hinge joint
C. Fixed joint
D. Ball and socket joint
12. Ritu has 500 cm³ of oxygen gas in a small cylinder. She wants to transfer all of it into another closed container. Which container volume can hold all the gas?
A. 250 cm³ container only
B. 400 cm³ container only
C. 550 cm³ container only
D. Any closed container of 250 cm³, 400 cm³, or 550 cm³
13. Which of the following changes can be easily reversed?
A. Baking a cake in an oven
B. Burning a candle
C. Blowing air into a rubber balloon without bursting it
D. Cooking food
14. Transmission electric lines across towers are not stretched too tightly during installation in summer because:
A. Expansion takes place in winter.
B. Contraction takes place in winter due to lower temperature.
C. Expansion takes place in summer and contraction in winter.
D. Thermal changes do not affect metal cables.
15. Deficiency of Vitamin C in the human diet causes scurvy, while deficiency of Vitamin D in toddlers leads to bone deformities (rickets). Which statement is CORRECT?
A. Vitamin C is fat-soluble and synthesized in sunlight.
B. Vitamin D is formed in our body in the presence of sunlight.
C. Vitamin C deficiency causes night blindness.
D. Vitamin D is abundantly present in citrus fruits.
SECTION C: ACHIEVERS SECTION (Questions 16–20)
16. Beena set up two aquatic plant experiments in sunlight for 9 hours. Set-up 1 contained Hydrilla in normal water. Set-up 2 contained Hydrilla in water with added sodium bicarbonate (baking soda). More oxygen collected in the test tube of Set-up 2. What is the best conclusion?
A. Baking soda directly releases oxygen gas.
B. Dissolved carbon dioxide increases the rate of photosynthesis in aquatic plants.
C. Photosynthesis decreases with higher carbon dioxide concentrations.
D. Plants do not need light when baking soda is present.
17. A student tested four unknown materials: P, Q, R, and S. P is elastic (Rubber band), Q is transparent and brittle (Glass/Electric bulb), R is hard and lustrous (Steel). Identify P, Q, and R respectively.
A. P – Steel, Q – Electric bulb, R – Rubber band
B. P – Rubber band, Q – Electric bulb, R – Steel
C. P – Electric bulb, Q – Rubber band, R – Steel
D. P – Steel, Q – Rubber band, R – Electric bulb
18. An iron nail is placed near the North pole of a bar magnet. What magnetisation is induced in the nail?
A. Only North pole at the near end.
B. A South pole at the end near the magnet and a North pole at the far end.
C. Only South pole throughout the nail.
D. No magnetism is induced.
19. Match the separation methods in Column-I with their appropriate application in Column-II:
(p) Flour and Iron filings -> (i) Handpicking
(q) Coconut oil and Water -> (ii) Magnet / Magnetic separation
(r) Pulses and Stone pebbles -> (iii) Decantation / Separating funnel
(s) Sugar in water -> (iv) Evaporation
A. p-(ii), q-(iii), r-(i), s-(iv)
B. p-(i), q-(ii), r-(iii), s-(iv)
C. p-(iv), q-(iii), r-(ii), s-(i)
D. p-(iii), q-(i), r-(iv), s-(ii)
20. Read the following statements regarding air and atmosphere:
Statement 1: Density of air decreases with increasing altitude.
Statement 2: Air dissolved in water supports aquatic life and can be released upon heating.
Statement 3: Nitrogen gas supports combustion.
Which statements are CORRECT?
A. Statements 1 and 2 only
B. Statements 2 and 3 only
C. Statements 1 and 3 only
D. All 1, 2, and 3
ANSWER KEY & DETAILED EXPLANATIONS
1. Answer: B (Grandfather / Grandmother)
Explanation: P’s son R is married to T (so T is P’s daughter-in-law). T is the daughter of Q. T has a daughter A, which makes A the child of R and T. Thus, A is the grandchild of P. Hence, P is the Grandfather (or Grandmother) of A.
2. Answer: B (I/9)
Explanation: Look at the positions of letters in the English alphabet: D is 4th letter -> $1^2 = 1$; I is 9th letter -> $3^2 = 9$; P is 16th letter -> $4^2 = 16$; Y is 25th letter -> $5^2 = 25$. The numerical values represent the squares of position/pattern indices ($1^2, 3^2, 4^2, 5^2$). Thus, the missing term is I/9.
3. Answer: A (63251)
Explanation: The letters are coded based on alphabetical position + 2 offset or specific position assignment: T=20+2=22… Following the consistent transformation rule derived from NEWS, TEACH translates to 63251.
4. Answer: B (19)
Explanation: Substituting the given operators:
‘-‘ becomes ‘+’, ‘x’ becomes ‘÷’, ‘÷’ becomes ‘-‘, ‘+’ becomes ‘x’.
Expression: $20 + (8 \div 4) – (3 \times 2) = 20 + 2 – 6 = 19$.
5. Answer: D (South)
Explanation: Initial facing direction = West ($270^\circ$).
Anti-clockwise turn of $225^\circ$: $270^\circ – 225^\circ = 45^\circ$ (South-West).
Clockwise turn of $135^\circ$: $45^\circ + 135^\circ = 180^\circ$ (South).
Net turn = $225^\circ – 135^\circ = 90^\circ$ anti-clockwise from West, which points directly South.
6. Answer: B (ᙠ⅃Uᙠ)
Explanation: In a plane mirror, the image undergoes lateral inversion (left and right sides are reversed). The individual letters as well as their sequence are reversed from left to right, yielding ᙠ⅃Uᙠ.
7. Answer: C (X > Y > Z)
Explanation: The magnetic strength of a magnet is proportional to the quantity of iron filings attracted to its poles. Since Magnet X attracted the maximum filings, Y moderate, and Z the least, the order of strength is $X > Y > Z$.
8. Answer: B (The displacement is zero.)
Explanation: In 1 hour, the minute hand completes one full circle ($360^\circ$) and returns exactly to its initial starting point. Since initial and final positions coincide, the net displacement is zero. Distance covered equals the circumference ($2\pi r$), so speed is non-zero.
9. Answer: A (Heat the magnet red hot and let it cool in the East-West direction.)
Explanation: Heating a magnet causes thermal agitation of its magnetic domains. Cooling it in the East-West direction prevents the Earth’s geomagnetic field (which acts North-South) from realigning the domains, ensuring complete demagnetisation.
10. Answer: C (X – Flax, Z – Wool)
Explanation: Flax is a plant stem fiber. Wool is obtained from sheep/goats by shearing fleece without causing harm to the animal.
11. Answer: B (Hinge joint)
Explanation: The knee joint connects the femur (thigh bone) and tibia (shin bone). It is a hinge joint allowing back and forth movement in one plane, similar to the hinges of a door.
12. Answer: D (Any closed container of 250 cm³, 400 cm³, or 550 cm³)
Explanation: Gases do not have a fixed volume or shape; they expand completely to fill the entire space of any closed container into which they are transferred.
13. Answer: C (Blowing air into a rubber balloon without bursting it)
Explanation: Blowing a balloon changes its shape and size physically. Releasing the air restores the balloon to its original state, making it a reversible physical change. Baking, burning, and cooking form new chemical substances and are irreversible.
14. Answer: B (Contraction takes place in winter due to lower temperature.)
Explanation: Metal cables expand in summer heat and contract during cold winter temperatures. If stretched tightly in summer, winter contraction will create excessive tension and break the lines.
15. Answer: B (Vitamin D is formed in our body in the presence of sunlight.)
Explanation: Vitamin D is synthesized by human skin exposed to sunlight (UV-B rays). Vitamin C is a water-soluble vitamin found in citrus fruits.
16. Answer: B (Dissolved carbon dioxide increases the rate of photosynthesis in aquatic plants.)
Explanation: Sodium bicarbonate (baking soda) dissolves in water to release carbon dioxide gas ($CO_2$). Higher $CO_2$ concentration accelerates the rate of photosynthesis, resulting in increased oxygen production.
17. Answer: B (P – Rubber band, Q – Electric bulb, R – Steel)
Explanation: Elasticity is characteristic of rubber; transparency and electrical utility describe glass bulbs; strength, metallic luster, and hardness characterize steel.
18. Answer: B (A South pole at the end near the magnet and a North pole at the far end.)
Explanation: Magnetic induction causes an opposite pole (South) to be induced at the end closer to the North pole of the magnet, and a similar pole (North) at the far end.
19. Answer: A (p-(ii), q-(iii), r-(i), s-(iv))
Explanation: Magnetic separation removes iron from flour; immiscible liquids (oil and water) are separated by decantation/separating funnel; stone pebbles are picked by hand from pulses; dissolved sugar is recovered by evaporating water.
20. Answer: A (Statements 1 and 2 only)
Explanation: Statement 1 is correct (air pressure/density decreases with altitude). Statement 2 is correct (dissolved air supports aquatic organisms and bubbles out when heated). Statement 3 is false because Nitrogen is an inert gas that suppresses combustion, whereas oxygen supports combustion.
Class 6 NSO practice paper