📘 Welcome
Hi User, you have selected Read Mode.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
Q1. When a plastic ruler is rubbed with a woollen cloth, it gains the ability to attract small pieces of paper. This is called:
When a plastic ruler is rubbed with a woollen cloth, electrons are transferred from one material to the other due to friction. This causes the ruler to become electrically charged, and it can then attract small pieces of paper. This process is called charging by friction or rubbing. Magnetism is a different phenomenon, and heating or evaporation are not related to this effect.
Q2. How many types of electric charges are there?
There are two types of electric charges: positive charge and negative charge. Protons carry positive charge and electrons carry negative charge. These are the only two types of charges found in nature. Like charges repel and opposite charges attract each other.
Q3. Like charges:
Like charges (positive-positive or negative-negative) repel each other. This is one of the fundamental laws of electricity. Opposite charges attract each other. Repulsion is a key property used in devices like electroscopes to detect charge.
Q4. Opposite charges:
Opposite charges (positive and negative) attract each other. This is why electrons (negative) are attracted to protons (positive) in an atom. Attraction between opposite charges is what holds atoms together and causes static electricity effects.
Q5. When a glass rod is rubbed with a silk cloth, the glass rod becomes:
When a glass rod is rubbed with a silk cloth, electrons are transferred from the glass rod to the silk cloth. The glass rod loses electrons, so it becomes positively charged. The silk cloth gains electrons and becomes negatively charged. This is a standard example of charging by friction.
Q6. When a plastic or ebonite rod is rubbed with woollen cloth, the plastic rod becomes:
When a plastic or ebonite rod is rubbed with woollen cloth, electrons are transferred from the woollen cloth to the plastic rod. The plastic rod gains electrons, so it becomes negatively charged. The woollen cloth loses electrons and becomes positively charged. This is another standard example of charging by friction.
Q7. The device used to detect whether an object is charged or not is called:
An electroscope is a device used to detect whether an object is charged or not. It works on the principle of repulsion of like charges. A thermometer measures temperature, a barometer measures atmospheric pressure, and a microscope is used to see small objects. The electroscope is the correct instrument for detecting charge.
Q8. In an electroscope, when a charged object touches the metal disc, the leaves diverge (spread apart) because:
When a charged object touches the metal disc of an electroscope, charge flows to the leaves. Both leaves get the same type of charge. Since like charges repel, the leaves diverge (spread apart). The leaves do not become heavy or magnetic; the repulsion is the reason for their divergence.
Q9. If the leaves of a charged electroscope collapse (come together) when a certain object is brought near, it indicates that:
If the leaves collapse when an object is brought near, it means the object has the opposite charge to the electroscope. Opposite charges attract, and the induced opposite charge on the leaves causes them to collapse. If the object had the same charge, the leaves would diverge more. An uncharged object would not cause collapse.
Q10. Lightning is caused by:
Lightning is caused by the accumulation of electric charges in clouds. During a thunderstorm, friction between air and water droplets causes charges to separate. The lower part of the cloud becomes negatively charged and the upper part positively charged. When the charge build-up is large enough, a discharge occurs in the form of lightning.
Q11. During a thunderstorm, the lower part of a thundercloud usually becomes:
During a thunderstorm, the lower part of a thundercloud usually becomes negatively charged due to the movement of electrons. The upper part becomes positively charged. This separation of charges leads to the build-up of potential difference, which eventually results in lightning.
Q12. Lightning is a flow of:
Lightning is a flow of electric charge (electrons) between clouds or between a cloud and the Earth. It is a sudden and massive discharge of static electricity. The flow of electrons causes the bright flash of light and the thunderous sound.
Q13. Which of the following is a correct safety measure during lightning?
The safest place during lightning is inside a building or a car (with windows closed). Tall trees, open ground, and metal objects are dangerous because they attract lightning. Buildings and cars provide protection by conducting the charge safely to the ground.
Q14. A lightning conductor is a device used to:
A lightning conductor is a device used to protect buildings from lightning damage. It consists of a metal rod placed on the top of the building, connected to the ground by a thick wire. It attracts lightning and safely conducts the charge to the ground, preventing damage to the building.
Q15. Which of the following materials is commonly used to make a lightning conductor?
Copper is commonly used to make lightning conductors because it is a good conductor of electricity. Plastic, wood, and glass are insulators and would not conduct the charge safely to the ground. Copper provides a low-resistance path for the lightning current.
Q16. An earthquake is caused by:
An earthquake is caused by the sudden movement of tectonic plates beneath the Earth’s surface. When these plates move, they release energy in the form of seismic waves, causing the ground to shake. Heavy rainfall, strong winds, and volcanic eruptions (though volcanic eruptions can trigger earthquakes) are not the primary causes.
Q17. The point inside the Earth where an earthquake originates is called the:
The point inside the Earth where an earthquake originates is called the focus (or hypocentre). It is the location where the sudden movement of rocks occurs. The epicentre is the point on the Earth’s surface directly above the focus. A fault line is the crack in the Earth’s crust.
Q18. The point on the Earth’s surface directly above the earthquake origin is called the:
The epicentre is the point on the Earth’s surface directly above the focus (hypocentre) of an earthquake. It is where the earthquake is felt most strongly. The focus is underground, and the epicentre is on the surface. The terms focus, hypocentre, and epicentre are all related but refer to different locations.
Q19. The instrument used to measure and record earthquakes is called:
A seismograph is the instrument used to measure and record earthquakes. It detects the seismic waves produced by an earthquake and records them on a seismogram. A barometer measures atmospheric pressure, a thermometer measures temperature, and an electroscope detects electric charge.
Q20. The magnitude (strength) of an earthquake is measured on the:
The magnitude (strength) of an earthquake is measured on the Richter scale. It is a logarithmic scale that quantifies the energy released by an earthquake. The Celsius and Fahrenheit scales are for temperature, and the decibel scale is for sound intensity.
Q21. Which of the following is a correct safety measure during an earthquake if you are indoors?
During an earthquake, if you are indoors, you should take cover under a sturdy table or desk and hold on. This protects you from falling objects. Windows, chandeliers, and running outside during shaking can be dangerous due to falling debris. The “Drop, Cover, and Hold On” method is the recommended safety measure.
Q22. Which of the following is a correct safety measure during an earthquake if you are outdoors?
If you are outdoors during an earthquake, you should move to an open area away from buildings, trees, and power lines. These structures can collapse or fall, causing injury. Running towards buildings or standing under trees is dangerous. An open area is the safest place.
Q23. If you are inside a moving car during an earthquake, you should:
If you are in a moving car during an earthquake, you should stop the car in an open area and stay inside until the shaking stops. Parking under a bridge is dangerous because bridges can collapse. Getting out of the car during shaking is also unsafe due to falling debris. Staying inside the car provides some protection.
Q24. The transfer of charge from a charged object to the Earth is called:
Earthing (or grounding) is the process of transferring charge from a charged object to the Earth. This neutralizes the object. It is done by connecting the object to the Earth through a conductor. Charging by friction is how objects become charged, induction is charging without contact, and repulsion is a force between like charges.
Q25. When a positively charged object is brought near a neutral electroscope, the leaves diverge slightly even without touching. This is due to:
When a charged object is brought near a neutral electroscope without touching, the leaves diverge due to charging by induction. The charged object induces opposite charges on the leaves, causing them to repel each other. This is a temporary effect and the leaves collapse when the charged object is removed.
Q26. A charged object can lose its charge if it is touched by a human hand because:
When a charged object is touched by a human hand, the charge transfers through the body to the Earth (earthing). This neutralizes the object. The hand provides a path for the charge to flow to the ground. The charge is not destroyed; it is simply transferred away.
Q27. During lightning, it is unsafe to take shelter under a tree because:
During lightning, it is unsafe to take shelter under a tree because trees are tall and contain moisture, which makes them good conductors of electricity. Lightning tends to strike tall objects, and a person under a tree could be electrocuted. Trees do not attract lightning intentionally, but their height and conductivity make them a target.
Q28. Which of the following is NOT a safe practice during a thunderstorm?
Using a landline telephone during a thunderstorm is unsafe because the phone line can conduct lightning. Unplugging electrical appliances, avoiding contact with plumbing, and staying inside a car are all safe practices. Landline phones should be avoided; mobile phones are safer because they have no wires.
Q29. When two different materials are rubbed together, the material that loses electrons becomes:
When two different materials are rubbed together, electrons are transferred from one material to the other. The material that loses electrons becomes positively charged because it has more protons than electrons. The material that gains electrons becomes negatively charged. This is the basis of charging by friction.
Q30. The best way to protect a tall building from lightning damage is to install:
The best way to protect a tall building from lightning damage is to install a lightning conductor. It safely conducts the lightning current to the ground, protecting the building from fire and structural damage. Flagpoles, water tanks, and un-earthed antennas are not effective lightning protection devices.
Q31. The outermost layer of the Earth where earthquakes occur is called the:
The outermost layer of the Earth is called the crust. Earthquakes occur in the crust when tectonic plates move. The core is the innermost layer, the mantle is between the core and the crust, and magma is molten rock inside the Earth. The crust is where we live and where earthquakes originate.
Q32. The region where two tectonic plates meet is called a:
The region where two tectonic plates meet is called a fault line or plate boundary. These are the areas where earthquakes and volcanic activity are most common. A volcano is a mountain formed by eruptions, a mountain peak is a high point, and an ocean trench is a deep depression in the sea floor.
Q33. Which of the following is a safe action during an earthquake if you are in bed?
If you are in bed during an earthquake, the safest action is to stay in bed and cover your head with a pillow. This protects you from falling objects. Jumping out of bed, running to the kitchen, or standing near a window are dangerous because you could be injured by falling debris.
Q34. The sudden shaking of the ground due to seismic waves is called:
The sudden shaking of the ground due to seismic waves is called an earthquake. It is caused by the movement of tectonic plates. A tsunami is a sea wave caused by an earthquake, a cyclone is a storm, and a flood is an overflow of water. The shaking itself is the earthquake.
Q35. After an earthquake, a large sea wave that can cause destruction is called a:
After an earthquake, a large sea wave that can cause destruction is called a tsunami. It is generated by underwater earthquakes, volcanic eruptions, or landslides. A hurricane and typhoon are tropical cyclones, and a tornado is a rotating column of air. A tsunami is specifically a seismic sea wave.
Q36. Which of the following is NOT a cause of earthquakes?
Heavy rainfall is not a cause of earthquakes. Earthquakes are caused by the movement of tectonic plates, volcanic eruptions, and underground nuclear tests. Heavy rainfall can cause landslides and floods, but it does not directly cause the ground shaking associated with earthquakes.
Q37. During an earthquake, if you are in a crowded public place (like a cinema or shop), you should:
In a crowded public place during an earthquake, you should drop, cover your head, and stay away from shelves and hanging objects. Running or pushing can cause panic and injury. Standing near windows is dangerous due to broken glass. The “Drop, Cover, and Hold On” method is the safest approach in any indoor setting.
Q38. A gold leaf electroscope is used to:
A gold leaf electroscope is used to detect the presence and type of electric charge. It can also indicate the relative amount of charge. It does not measure the exact amount of charge quantitatively, generate electricity, or store charge. It works on the principle of repulsion of like charges.
Q39. If a negatively charged rod touches the metal disc of a neutral electroscope, the leaves will:
When a negatively charged rod touches the metal disc of a neutral electroscope, electrons flow from the rod to the electroscope. Both leaves become negatively charged. Since like charges repel, the leaves diverge (spread apart). This is how an electroscope detects charge.
Q40. The best place to hide during an earthquake if you are indoors and no table is available is:
If no table is available, the best place to hide during an earthquake is against an inside wall (away from windows), covering your head and neck. Inside walls are less likely to collapse than outer walls. Windows, mirrors, and bookshelves are dangerous because they can break or fall. An inside wall provides some protection from falling debris.
Q41. Lightning conductors should be installed on:
Lightning conductors should be installed on all buildings, especially tall ones, to protect them from lightning strikes. Tall buildings are more likely to be struck by lightning. Even smaller buildings in areas prone to thunderstorms should have lightning protection. It is a safety measure for all types of structures.
Q42. When a charged object is brought near a neutral conductor without touching, the side closer to the charged object gets opposite charge. This phenomenon is called:
When a charged object is brought near a neutral conductor without touching, the side closer to the charged object gets the opposite charge due to induction. This is called charging by induction. The charges are rearranged within the conductor. Conduction requires contact, friction involves rubbing, and radiation is unrelated.
Q43. Which of the following statements about earthquakes is correct?
Earthquakes cannot be predicted accurately in terms of time and location. However, we can be prepared by taking safety measures and building earthquake-resistant structures. India is an earthquake-prone region, and earthquakes can happen on land as well as under the ocean. Preparation is the key to minimizing damage.
Q44. During lightning, it is safe to use a mobile phone because:
During lightning, it is safe to use a mobile phone because mobile phones have no wires that can conduct lightning. Landline phones are dangerous because they have external wires that can carry lightning strikes. Mobile phones are wireless and do not provide a direct path for lightning to reach the user.
Q45. A simple electroscope can be made at home using:
A simple electroscope can be made at home using a glass bottle (or jar), a metal hook, and two thin aluminium foil strips. The foil strips act as the leaves. When a charged object touches the hook, the foil strips diverge. The other materials listed are not suitable for making an electroscope.
Q46. The process of removing excess charge from an object by connecting it to the Earth is called:
Earthing (or grounding) is the process of removing excess charge from an object by connecting it to the Earth. This provides a path for the charge to flow to the ground, neutralizing the object. Charging is the process of giving charge, induction is charging without contact, and friction is charging by rubbing.
Q47. If you are outdoors during an earthquake and there are no open areas, you should:
If you are outdoors during an earthquake and there are no open areas, you should lie flat against a building wall, covering your head. This reduces the risk of being hit by falling debris. Standing close to a wall is not safe because debris can fall from above. Running inside a building or climbing a tree during shaking is dangerous.
Q48. A lightning strike can heat the air to a temperature of about:
A lightning strike can heat the air to a temperature of about 30,000°C (or even higher). This extreme heat causes the air to expand rapidly, producing the thunder we hear. 100°C is the boiling point of water, 1000°C is much lower, and 500°C is too low. The temperature of lightning is extremely high.
Q49. During an earthquake, the safest place inside a room is:
The safest place inside a room during an earthquake is under a heavy table or desk. This provides protection from falling objects. Windows, bookshelves, and weak doorways are dangerous. A doorway may only be safe in a strong wooden frame house, but the table/desk is generally the safest option.
Q50. Which of the following is a correct precaution to take before an earthquake (preparedness)?
Before an earthquake, a correct precaution is to secure tall furniture like bookshelves and water heaters to the wall. This prevents them from toppling over during shaking. Keeping heavy objects on high shelves, keeping flammable liquids near the stove, and blocking exit doors are unsafe practices. Securing furniture is a key preparedness measure.