Sunday Smart IQ Quiz Series | Answer Key For All Stages | Apex Edutech Solutions

🧠 Sunday Smart IQ Challenge – All Stages Answer Key & Explanations

Sunday Smart IQ Challenge is designed as per NEP 2020 to build logical thinking, reasoning, observation, pattern recognition and real-life problem-solving across all four stages – Foundation, Preparatory, Middle and Secondary.

Use this page as a self-check tool for students and a quick reference for teachers & parents. Each question has the correct option and a one-line explanation.

🟦 Foundation Stage – Answer Key with Explanations (Grades 1–2)

Q.No	Correct Answer	Brief Explanation
1	B – Triangle	A triangle is the only shape with exactly 3 sides.
2	D – Apple	Cat, dog and lion are animals; apple is a fruit, so it is odd one out.
3	B – 15	15 comes immediately after 14 in counting.
4	B – Bird	A bird can fly, the other objects cannot.
5	A – 🔵	The pattern repeats 🔵🔴, so the next again is 🔵.
6	A – Elephant	Among the options, elephant is the biggest.
7	C – 8	A spider has 8 legs.
8	B – Eyes	We use our eyes to see.
9	C – Mango	Mango is a fruit; others are vegetables.
10	B – 10	The pattern is even numbers: 2,4,6,8,10…
11	A – Cow	Cows commonly give us milk.
12	B – Square	A square has 4 equal sides.
13	B – Pen	We use a pen for writing.
14	A – Shoes	We wear shoes on our feet.
15	B – Fire	Fire is hot; ice and snow are cold.
16	B – 2	2 is the smallest among 8,2,6,9.
17	A – Fish	Fish lives in water.
18	B – Pink	Pink is a colour; others are objects.
19	B – Spoon	We normally eat soup with a spoon.
20	B – Rabbit	Rabbit runs faster than turtle, snail or sloth.
21	B – Moon	We usually see the moon at night.
22	A – Scissors	Scissors are used to cut paper.
23	B – Water	Plants need water to grow.
24	B – Triangle	Triangle is a shape; others are objects.
25	C – 19	19 comes just before 20.

🟧 Preparatory Stage – Answer Key with Explanations (Grades 3–5)

Q.No	Correct Answer	Brief Explanation
1	B – 12	12 is a multiple of 6 (6 × 2).
2	B – Circle	A circle has no straight sides.
3	C – Small	“Tiny” and “small” mean almost the same.
4	C – 7	7 has exactly two factors (1 and 7), so it is prime.
5	A – 35	The pattern adds 5 each time: 15,20,25,30,35…
6	B – Mars	Mars is called the Red Planet.
7	A – Snake	Snakes have a backbone, so they are vertebrates.
8	C – Leaf	Leaves prepare food using photosynthesis.
9	C – Square	A square has many lines of symmetry.
10	A – 0°C	Pure water freezes at 0 degrees Celsius.
11	C – Aeroplane	Aeroplanes travel faster than cars, cycles or walking.
12	B – Edison	Thomas Edison is credited with inventing the practical light bulb.
13	D – Metal	Metals allow electricity to pass easily, so they are conductors.
14	B – East	The sun appears to rise in the east.
15	A – Oxygen	During photosynthesis, plants release oxygen.
16	B – Pacific	The Pacific Ocean is the largest ocean on Earth.
17	C – Heart	The heart pumps blood throughout the body.
18	C – 1/3 shaded	The correct figure has exactly one-third of the shape shaded.
19	B – Shoe stopping while running	Friction between shoe and ground slows you down.
20	D – Potato	Rose, lily and sunflower are flowers; potato is a root vegetable.
21	B – Diwali	Diwali is known as the festival of lights.
22	C – Both same	1 kg of cotton and 1 kg of iron have equal mass.
23	D – 6	6 divides 24 exactly (24 ÷ 6 = 4), so it is a factor.
24	C – Cow	Cows eat plants, so they are herbivores.
25	B – Meter	Metres are used to measure length or distance.

🟩 Middle Stage – Answer Key with Explanations (Grades 6–8)

Q.No	Correct Answer	Brief Explanation
1	B – 36	36 = 6 × 6, so it is a perfect square.
2	C – Jupiter	Jupiter has the maximum known moons in our solar system.
3	A – Tagore	Rabindranath Tagore wrote India’s National Anthem.
4	B – Condensation	Condensation is the change of water vapour to liquid.
5	B – 3.14	π is approximately 3.14.
6	C – Newton’s 3rd	Newton’s third law explains action and reaction forces.
7	C – Wind	Wind energy gets renewed naturally, so it is renewable.
8	A – Newton	The SI unit of force is newton (N).
9	B – Kidney	Kidneys filter and purify blood.
10	C – Mercury	Mercury is the only metal liquid at room temperature.
11	C – Equilateral	An equilateral triangle has all three sides equal.
12	B – H₂O	The chemical formula of water is H₂O.
13	B – Mantle	Magma is found mainly in the Earth’s mantle.
14	B – Earth’s revolution	Earth’s revolution around the sun causes seasons.
15	C – Carbon dioxide	During respiration, organisms release CO₂.
16	C – Rubber	Rubber does not allow electricity to flow easily; it is an insulator.
17	B – Femur	The thigh bone (femur) is the longest bone in the body.
18	B – 50	25% of 200 = 25/100 × 200 = 50.
19	C – Mitochondria	Mitochondria are called the powerhouse of the cell.
20	A – Ganga	The Ganga is the longest river within India.
21	C – 2	2 is the smallest prime number.
22	B – Graphite	Pencil “lead” is actually made of graphite.
23	C – Vacuum	Sound needs a medium; it cannot travel through a vacuum.
24	B – Cerebellum	The cerebellum helps to maintain body balance.
25	B – 100°C	Water boils at 100 degrees Celsius at normal pressure.

🟥 Secondary Stage – Answer Key with Explanations (Grades 9–10)

Q.No	Correct Answer	Brief Explanation
1	B – Law of Conservation of Energy	This law states energy can neither be created nor destroyed, only transformed.
2	B – x² – 5x + 6 = 0	A quadratic equation has x² as the highest power of x.
3	B – Ampere	The SI unit of electric current is ampere (A).
4	B – B. R. Ambedkar	Dr. B. R. Ambedkar is known as the Father of the Indian Constitution.
5	B – Atom	An atom is the smallest particle of an element that retains its properties.
6	B – 1	By definition, sin 90° = 1.
7	B – Carbon dioxide	CO₂ is a major greenhouse gas responsible for global warming.
8	C – Brain	The brain controls all voluntary and involuntary actions.
9	C – √2	√2 cannot be expressed as a simple fraction, so it is irrational.
10	B – Rectifier	A rectifier converts alternating current (AC) to direct current (DC).
11	B – Newton	Sir Isaac Newton discovered the law of gravitation.
12	C – O–	Blood group O negative can donate to all groups, so it is universal donor.
13	C – Melting	Melting absorbs heat, so it is an endothermic process.
14	B – Venus	Venus rotates very slowly, so one day on Venus is very long.
15	C – 90	20% of 450 = 20/100 × 450 = 90.
16	C – Mitochondria	Mitochondria release energy, hence called the powerhouse of the cell.
17	D – Force	Force has both magnitude and direction, so it is a vector quantity.
18	A – Ozone layer	The ozone layer absorbs harmful UV radiation from the sun.
19	C – Sodium	Sodium is highly reactive, especially with water and air.
20	B – Deoxyribonucleic Acid	DNA stands for Deoxyribonucleic Acid, the genetic material.
21	C – Right triangle	A right triangle has one angle equal to 90°.
22	A – 3×10⁸ m/s	Speed of light in vacuum is approximately 3 × 10⁸ m/s.
23	B – Citric acid	Lemons contain citric acid, giving them a sour taste.
24	C – Coal	Coal is a fossil fuel and cannot be renewed quickly, so it is non-renewable.
25	B – Na	The chemical symbol ‘Na’ is used for sodium.

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