⚛️ Physics · Topic 10 of 10
Start with the study notes on Natural Phenomena & Solar System (definitions, examples and a quick revision), then work through 60 practice questions, each with the correct answer and a clear explanation of why it is right. When you are ready, take this topic as an interactive quiz to test yourself.
Topic overview
Rubbing two objects together moves electric charge from one to the other, so both become charged. Charges that stay on a surface are called static charges.
Examples:
There are two kinds of charge: positive (+) and negative (–).
This is the same pattern as the poles of a magnet.
Remember: Rubbing does not create charge; it only transfers it. A glass rod rubbed with silk becomes positive, because the silk takes some negative charge from it.
An electroscope shows whether an object is charged. Its two thin metal strips spread apart when a charged object touches it.
In a thunderstorm, large charges build up in the clouds. When the charge becomes large enough, it jumps to another cloud or to the ground as a giant spark. This is lightning.
Example: Around 1752, Benjamin Franklin showed that lightning is electrical.
A lightning conductor is a metal rod on top of a tall building, joined to the ground by a thick wire. It carries the lightning's charge safely into the Earth.
Passing charge into the Earth is called earthing. Electrical appliances are earthed for the same reason.
An earthquake is a sudden shaking of the Earth's surface.
The Earth's outer layer is broken into huge slabs called tectonic plates, which move very slowly. When they suddenly slip or push against each other, the ground shakes.
Example: In earthquake zones, buildings use strong frames and light materials, so they are less likely to collapse.
The Sun is a star: a huge ball of hot, glowing gases that makes its own light and heat. It is the star nearest to the Earth.
The Solar System is the Sun and everything that goes round it. The Sun's gravity keeps eight planets moving in paths called orbits.
Mercury · Venus · Earth · Mars · Jupiter · Saturn · Uranus · Neptune
Remember: To remember the order: My Very Efficient Mother Just Served Us Nuts.
Remember: Pluto has been classed as a dwarf planet since 2006, so it is not one of the eight planets.
The Moon is the Earth's natural satellite: a body that goes round a planet. It has no light of its own and shines by reflecting sunlight.
Example: The phases of the Moon (new moon, crescent, half moon, full moon) are the changing parts of its sunlit side that we see over about a month.
Artificial satellites are made by people and launched into orbit, for weather forecasting, communication, TV and navigation.
| Misconception | Correct understanding |
|---|---|
| Rubbing creates electric charge. | Rubbing only transfers charge from one object to the other. |
| Mercury is the hottest planet because it is closest to the Sun. | Venus is hotter, because its thick atmosphere traps heat. |
| The Sun is a planet, and the Moon is a star. | The Sun is a star; the Moon is a satellite of the Earth. |
| A shooting star is a falling star. | It is a meteor: a small bit of space rock burning up in our air. |
| A tall tree is a safe shelter in a thunderstorm. | Lightning often strikes tall objects; a building or a closed car is safer. |
Why does a rubbed comb pick up bits of paper?
Rubbing charges the comb, and the charged comb attracts the light bits of paper.
What is lightning?
A giant spark that happens when charges built up in clouds jump to another cloud or to the ground.
How does a lightning conductor protect a building?
It carries the lightning's charge safely down a thick wire into the Earth.
What causes earthquakes?
Sudden movements of the Earth's tectonic plates.
Which instrument records earthquakes?
A seismograph.
Which is the largest planet?
Jupiter.
Why is Venus hotter than Mercury?
Its thick carbon dioxide atmosphere traps heat.
What causes day and night?
The Earth spinning on its axis once in about 24 hours.
Key takeaway: Electric charges cause lightning, moving plates cause earthquakes, and gravity holds the Sun's family of planets together.
Notes written by Velnov for Class 6–8 students, following the topics of the NCERT science syllabus.
Q1. medium
When you rub a plastic scale (or comb) on dry hair, it can attract small bits of paper. This is because the scale becomes:
Answer: A — Electrically charged (static electricity)
Rubbing transfers charge, so the scale becomes electrically charged. This static electricity lets it attract light objects like bits of paper. Such charges produced by rubbing are called static (still) charges.
Q3. medium
There are two kinds of electric charges:
Answer: A — Positive and negative
There are two types of electric charge: positive (+) and negative (-). Rubbing separates charges, making one object positively charged and the other negatively charged.
Q5. medium
A device used to detect whether an object is electrically charged is a/an:
Answer: A — Electroscope
An electroscope detects electric charge. A simple electroscope can be made with a jar, a metal rod and two thin strips of foil, which spread apart when touched by a charged object.
Q7. medium
Lightning is caused by the:
Answer: A — Buildup and sudden discharge of electric charges between clouds (or cloud and ground)
During a thunderstorm, charges build up in the clouds. When enough charge accumulates, it jumps across as a giant spark - lightning - between clouds, or between a cloud and the ground. It is a large-scale electric discharge.
Q9. medium
A device fitted on tall buildings to protect them from lightning is called a:
Answer: A — Lightning conductor (lightning rod)
A lightning conductor is a metal rod fixed on top of a building and connected to the ground by a thick wire. It safely carries the lightning's electric charge down into the Earth, protecting the building.
Q11. medium
The sudden shaking or trembling of the Earth's surface is called an:
Answer: A — Earthquake
An earthquake is a sudden shaking or trembling of the Earth's surface, caused by movements deep inside the Earth. It can cause great destruction to buildings and life.
Q13. medium
The instrument used to record earthquakes is a:
Answer: A — Seismograph
A seismograph records the vibrations (seismic waves) produced by an earthquake. The recording helps scientists measure the earthquake's strength and locate where it happened.
Q15. medium
Which is a safety measure during an earthquake if you are indoors?
Answer: A — Take shelter under a sturdy table and stay away from tall furniture and windows
During an earthquake, drop, cover under a strong table, and hold on. Stay away from heavy furniture, glass windows and mirrors. Do NOT use lifts. If outside, move to open ground away from buildings and power lines.
Q16. medium
Our Sun is a:
Answer: A — Star
The Sun is a star - a huge, hot ball of glowing gases that produces its own light and heat. It is the nearest star to Earth and the centre of our solar system.
Q18. medium
The planet CLOSEST to the Sun is:
Answer: A — Mercury
Mercury is the planet nearest to the Sun and also the smallest planet in the Solar System. It has no moons and takes the shortest time to orbit the Sun.
Q20. medium
The LARGEST planet in the Solar System is:
Answer: A — Jupiter
Jupiter is the largest planet in the Solar System - so big that over 1,000 Earths could fit inside it. It also has the most moons and a famous 'Great Red Spot' (a giant storm).
Q22. medium
Which planet is known as the 'Red Planet'?
Answer: A — Mars
Mars is called the 'Red Planet' because its surface is covered with reddish iron-oxide (rust) dust. It is a major target for space exploration in the search for signs of past life.
Q24. medium
Venus is often called the Earth's 'twin' or 'sister planet' because it:
Answer: A — Is nearly the same size as the Earth
Venus is similar in size and mass to the Earth, so it is called Earth's twin. However, it is very hot, has a thick poisonous atmosphere, and has no water or life.
Q26. medium
The natural satellite of the Earth is the:
Answer: A — Moon
The Moon is the Earth's only natural satellite. It revolves around the Earth and reflects sunlight, which is why it shines at night. It has no light of its own.
Q28. medium
The different shapes of the bright part of the Moon seen from Earth over a month are called the:
Answer: A — Phases of the Moon
The phases of the Moon (new moon, crescent, half, gibbous, full moon) are the changing shapes of the lit-up part of the Moon we see as it revolves around the Earth. One full cycle takes about a month.
Q30. medium
The huge system of billions of stars, gas and dust held together by gravity is called a:
Answer: A — Galaxy
A galaxy is an enormous collection of billions of stars, along with gas and dust, held together by gravity. Our Sun is one star in a galaxy called the Milky Way.
Q32. medium
A group of stars that appears to form a recognisable pattern or shape in the sky is called a:
Answer: A — Constellation
A constellation is a group of stars that forms a recognisable pattern. Examples include Ursa Major (the Great Bear / Saptarshi), Orion, and Cassiopeia. Ancient people used constellations to find directions.
Q35. medium
Stars appear to twinkle at night, but planets do not (much). Stars are seen because they:
Answer: A — Produce their own light (they are like distant suns)
Stars are huge, hot balls of gas that produce their own light, like our Sun. They appear as tiny twinkling points because they are extremely far away. Planets shine by reflecting the Sun's light.
Q37. medium
A 'shooting star' streaking across the night sky is actually a:
Answer: A — Meteor (a small body burning up in the atmosphere)
A 'shooting star' is not a star at all - it is a meteor: a small piece of rock or dust from space that burns up brightly due to friction as it enters the Earth's atmosphere at high speed.
Q39. medium
A body that revolves around the Sun in a long, stretched orbit and develops a bright glowing TAIL when near the Sun is a:
Answer: A — Comet
A comet is a body of ice, dust and rock that orbits the Sun in a very elongated path. When it comes close to the Sun, it heats up and forms a glowing head and a long tail that always points away from the Sun.
Q41. medium
The path along which a planet revolves around the Sun is called its:
Answer: A — Orbit
An orbit is the fixed path along which a planet revolves around the Sun (or a satellite around a planet). The planets move in slightly oval (elliptical) orbits.
Q43. medium
The revolution of the Earth around the Sun takes about:
Answer: A — One year (365 1/4 days)
The Earth takes about 365 and a quarter days (one year) to revolve once around the Sun. The extra quarter days add up to one extra day every 4 years - a 'leap year' (February has 29 days).
Q45. medium
Which of these is NOT a planet?
Answer: A — The Sun
The Sun is a star, not a planet. Mars, Jupiter and Neptune are planets. Planets do not produce their own light; the Sun does.
Q47. medium
The two planets that lie BETWEEN the Earth and the Sun (the 'inner' neighbours) are:
Answer: A — Mercury and Venus
Mercury and Venus lie between the Earth and the Sun. Because of this, they are sometimes seen near the horizon just after sunset or before sunrise (Venus is the bright 'evening/morning star').
Q49. medium
Which effect protects electrical appliances by carrying dangerous charge safely to the ground?
Answer: A — Earthing (grounding)
Earthing connects the metal body of an appliance to the ground through a wire. If there is a fault, the dangerous charge/current flows safely into the Earth instead of giving the user a shock.
Q51. medium
Which of these is a possible warning/effect that helps in earthquake-resistant building design?
Answer: A — Using lightweight materials and strong frames, especially in earthquake-prone zones
In earthquake-prone areas, buildings are designed to resist shaking - using lightweight materials, strong steel/concrete frames, and good foundations. Mud houses and poorly built structures are more likely to collapse.
Q53. medium
Which of these correctly matches the object with what it is?
Answer: A — Sun - star; Earth - planet; Moon - satellite
The Sun is a star (produces its own light), the Earth is a planet (revolves around the Sun), and the Moon is a satellite (revolves around the Earth). Getting these categories right is important.
Q55. medium
Which planet is known as the 'Blue Planet'?
Answer: A — Earth
The Earth is called the 'Blue Planet' because about 71% of its surface is covered with water, giving it a blue appearance from space. (Neptune and Uranus also look bluish due to gases, but Earth is 'the' Blue Planet.)
Q57. medium
The Sun is important for life on Earth mainly because it provides:
Answer: A — Light and heat energy
The Sun provides the light and heat energy essential for life on Earth - driving weather, the water cycle, and photosynthesis in plants (the base of the food chain). Without the Sun, there would be no life on Earth.
Q58. medium
Like electric charges repel and unlike charges attract. This behaviour is similar to that of:
Answer: A — Magnetic poles (like poles repel, unlike poles attract)
Just like magnetic poles (where like poles repel and unlike attract), like electric charges repel and unlike charges attract. Both electric and magnetic forces are non-contact forces.
Q60. medium
The Moon has no atmosphere and no sound. Which statement about the Moon is TRUE?
Answer: A — It is a non-luminous satellite of the Earth that reflects sunlight
The Moon is the Earth's natural satellite. It is non-luminous and shines only by reflecting sunlight. It has no atmosphere, so there is no air, weather or sound on it.
Q2. hard
The electric charge produced by rubbing two objects together is called:
Answer: A — Static charge (static electricity)
Charges produced by rubbing objects together are static charges (they stay on the surface). This is why they are called 'static electricity', as opposed to the moving charges of current electricity.
Q4. hard
Like charges (both positive, or both negative) ______ each other, while unlike charges attract.
Answer: A — Repel
Like charges repel (push apart) and unlike charges attract (pull together) - just like magnetic poles. Two objects with the same type of charge push each other away.
Q6. hard
The process of transferring the charge of a charged object to the Earth is called:
Answer: A — Earthing (grounding)
Earthing is the transfer of electric charge to the Earth (which can absorb large amounts of charge). Buildings use earthing/lightning conductors, and appliances are earthed for safety.
Q8. hard
The American scientist who showed that lightning is an electric spark, through his famous kite experiment, was:
Answer: A — Benjamin Franklin
Benjamin Franklin demonstrated (around 1752) that lightning is a form of electricity, through his risky kite-and-key experiment. He also invented the lightning conductor to protect buildings.
Q10. hard
During a thunderstorm, the SAFEST place to be is:
Answer: A — Inside a building or a closed vehicle
During lightning, one should stay inside a building or a closed (metal-bodied) car. Open fields, hilltops and tall isolated trees are dangerous, as lightning tends to strike tall, exposed objects.
Q12. hard
Earthquakes are mainly caused by the movement of huge rocky plates that make up the Earth's outer layer. These are called:
Answer: A — Tectonic (crustal) plates
The Earth's outer layer is made of large moving pieces called tectonic plates. When these plates suddenly slip or collide, they release energy that shakes the ground - an earthquake.
Q14. hard
The strength (magnitude) of an earthquake is measured on the:
Answer: A — Richter scale
The magnitude of an earthquake is measured on the Richter scale. Earthquakes above magnitude 7 are very severe and can cause widespread destruction.
Q17. hard
The Solar System consists of the Sun and the objects that revolve around it. How many PLANETS are there in our Solar System?
Answer: A — Eight
There are eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. (Pluto was reclassified as a 'dwarf planet' in 2006, so it is no longer counted among the eight planets.)
Q19. hard
The correct order of the planets from the Sun (nearest first) is:
Answer: A — Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
From the Sun outward: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. A common memory phrase is 'My Very Efficient Mother Just Served Us Nuts'.
Q21. hard
The planet famous for its bright, beautiful RINGS is:
Answer: A — Saturn
Saturn is famous for its spectacular rings, made of ice and rock particles. It is the second-largest planet. (Jupiter, Uranus and Neptune also have faint rings, but Saturn's are the brightest.)
Q23. hard
The HOTTEST planet in the Solar System is:
Answer: A — Venus
Venus is the hottest planet because its thick atmosphere of carbon dioxide traps heat (a runaway greenhouse effect), even though Mercury is closer to the Sun. Venus is also the brightest planet in our sky.
Q25. hard
The only planet known to support LIFE is:
Answer: A — Earth
Earth is the only planet known to support life, because it has liquid water, a suitable temperature, oxygen in its atmosphere, and protection from harmful radiation. It appears blue from space (the 'Blue Planet').
Q27. hard
The Moon does not shine by its own light. It appears bright because it:
Answer: A — Reflects the Sun's light
The Moon is a non-luminous body. We see it because it reflects sunlight toward the Earth. The changing amounts of the sunlit Moon we see cause the different phases of the Moon.
Q29. hard
A small body that revolves around a planet is called a:
Answer: A — Satellite (moon)
A satellite is a body that revolves around a planet. The Moon is Earth's natural satellite. Many planets, like Jupiter and Saturn, have many moons. Man-made satellites are also launched to orbit the Earth.
Q31. hard
Our Sun and Solar System belong to a galaxy called the:
Answer: A — Milky Way (Akash Ganga)
Our Solar System is part of the Milky Way galaxy (called 'Akash Ganga' in India). On a clear, dark night, the Milky Way appears as a faint band of light stretching across the sky.
Q33. hard
The prominent constellation seen in the northern sky, also called the Great Bear or 'Saptarshi', is:
Answer: A — Ursa Major
Ursa Major (the Great Bear, or 'Saptarshi' - the seven sages) is a well-known constellation. Its seven bright stars form a shape like a big ladle. It helps to locate the Pole Star (North Star).
Q34. hard
The star that appears almost stationary in the northern sky (used to find the North direction) is the:
Answer: A — Pole Star (Dhruv Tara)
The Pole Star (Dhruv Tara), located roughly above the Earth's North Pole, appears fixed in the sky while other stars seem to move around it. This is why it has long been used to find the North direction at night.
Q36. hard
A small, rocky body that revolves around the Sun, mostly found in a belt between Mars and Jupiter, is called an:
Answer: A — Asteroid
Asteroids are small rocky bodies orbiting the Sun, most of them in the asteroid belt between Mars and Jupiter. They are like leftover building material from the formation of the Solar System.
Q38. hard
A meteor that does NOT burn up completely and lands on the Earth's surface is called a:
Answer: A — Meteorite
If a meteor survives its fiery passage through the atmosphere and reaches the ground, it is called a meteorite. Large meteorites can create craters on the Earth's surface.
Q40. hard
The force that keeps the planets revolving around the Sun (and the Moon around the Earth) is:
Answer: A — Gravitational force (gravity)
The Sun's strong gravitational force pulls on the planets and keeps them in their orbits. Similarly, the Earth's gravity keeps the Moon revolving around it. Gravity holds the whole Solar System together.
Q42. hard
The spinning of the Earth on its own axis causes:
Answer: A — Day and night
The Earth rotates on its axis once in about 24 hours. The side facing the Sun has day and the side away from the Sun has night. As the Earth spins, day and night follow each other.
Q44. hard
Man-made objects launched into space to orbit the Earth for communication, weather and other uses are called:
Answer: A — Artificial satellites
Artificial (man-made) satellites are launched into orbit around the Earth for purposes like telecommunication, weather forecasting, television broadcasting, navigation (GPS) and remote sensing. India's satellites include the INSAT and IRS series.
Q46. hard
Why do planets NOT twinkle, while stars do?
Answer: A — Planets are much closer and appear as small discs (steady light), while stars are point-like and very far
Planets are relatively close and appear as tiny discs, so their light is steady. Stars are extremely far away and appear as points of light; the Earth's atmosphere bends this point-light unsteadily, making stars appear to twinkle.
Q48. hard
Which of these correctly describes the Sun?
Answer: A — It is the nearest star, a huge ball of hot glowing gases, and the source of energy for the Solar System
The Sun is the nearest star to Earth - a vast, extremely hot ball of glowing gases. It provides the light and heat energy that support life on Earth and holds the Solar System together with its gravity.
Q50. hard
Before lightning strikes, the safest action if you are in an open field is to:
Answer: A — Crouch low on the ground, away from tall objects and water
If caught in the open during lightning, crouch low with feet together and hands on knees, staying away from tall trees, poles, water and metal objects. Avoid lying flat, and never shelter under a tall isolated tree.
Q52. hard
Rubbing a glass rod with silk leaves the glass rod positively charged. This shows that during rubbing:
Answer: A — Charge is transferred from one object to the other
Rubbing does not create charge; it transfers charge from one object to the other. One object loses negative charge (becoming positive) and the other gains it (becoming negative). The total charge is conserved.
Q54. hard
Which statement about the Solar System is CORRECT?
Answer: A — The Sun is at the centre, and eight planets revolve around it held by gravity
The Sun is at the centre of the Solar System, and eight planets (with their moons), along with asteroids, comets and meteoroids, revolve around it, held by the Sun's gravity. The Moon revolves around the Earth, not directly around the Sun.
Q56. hard
Which overall statement about natural phenomena is CORRECT?
Answer: A — Static charge builds up by rubbing, lightning is a huge electric discharge, earthquakes come from moving plates, and lightning conductors and earthing keep us safe
Rubbing produces static charge; the buildup and sudden discharge of such charges in clouds causes lightning; earthquakes are caused by the movement of the Earth's tectonic plates; and safety devices like lightning conductors and earthing protect us from electrical dangers.
Q59. hard
Which of these is a DWARF planet, no longer counted among the eight main planets?
Answer: A — Pluto
Pluto was reclassified as a 'dwarf planet' in 2006 by astronomers, so it is no longer counted among the eight planets of the Solar System. Mars, Neptune and Mercury remain full planets.