Natural Phenomena MCQ

Answer: C) Earthing

Explanation: The process of transfer of charges from a charged object to the earth is called "earthing". When an object becomes charged, it has an excess of either positive or negative charges. This excess charge can be transferred to the earth, which is a large reservoir of charge and can absorb the excess charge.

Earthing is an important process in many electrical systems and devices. It is used to prevent electrical shocks and damage to the equipment caused by electrostatic discharge. 

For example, electrical appliances are often grounded to prevent static electricity buildup and to protect against electrical faults. In addition, many buildings and structures are grounded to protect against lightning strikes, which can be dangerous and damaging.

Therefore, option C) Earthing is the correct answer as it accurately describes the process of transferring charges from a charged object to the earth.

Answer: B) 2

Explanation: When two objects are rubbed together, they can gain or lose electrons, which are negatively charged subatomic particles. This transfer of electrons can result in two types of charges: positive and negative.

• The process of rubbing or friction can cause the electrons to move from one object to another, which can result in one object becoming positively charged (losing electrons) and the other becoming negatively charged (gaining electrons). 
• This is known as triboelectric charging.
• Therefore, the correct answer to the question "How many types of charges are gained by rubbing objects?" is 2, namely positive and negative charges.

Answer: C) Richter scale

Explanation: The power or magnitude of an earthquake is expressed on a scale called the Richter scale, which is named after American seismologist Charles Richter. 

• The Richter scale is a logarithmic scale, which means that each whole number increase in magnitude represents a tenfold increase in the amplitude of the seismic waves. 
• For example, an earthquake with a magnitude of 6.0 releases 10 times more energy than an earthquake with a magnitude of 5.0.

The Richter scale is widely used to measure the power of earthquakes, but it does have some limitations. For very large earthquakes, with magnitudes greater than 8.0, the Richter scale can become inaccurate and other scales such as the Moment Magnitude scale are used instead. Additionally, the Richter scale only measures the amplitude of the seismic waves and does not take into account other factors such as the duration or distance of the earthquake.

Therefore, option C) Richter scale is the correct answer.

Answer: C) Electrical discharge

Explanation: Lightning is a natural phenomenon that occurs during thunderstorms. It is an electrical discharge that occurs due to the buildup of electric charge in the atmosphere. 

• When the electric field becomes strong enough, it ionizes the air and creates a conductive path for the electric charge to flow through. 
• This creates a bright flash of light and a loud thunderclap. 
• The discharge can be very powerful and can cause damage to buildings and other structures. 
• Therefore, the correct answer is c) Electrical discharge.

Answer: B) Seismic wave

Explanation: Seismic waves are waves of energy that travel through the Earth's layers, and they are produced by natural phenomena such as earthquakes, volcanic eruptions, and landslides. 

• These waves can also be artificially produced by explosions, underground nuclear testing, and human activities such as fracking.
• Seismic waves are categorized into two types: body waves and surface waves. 
• Body waves travel through the Earth's interior and are responsible for the shaking felt during an earthquake. 
• They are further divided into two types: P waves (primary waves) and S waves (secondary waves). 
• P waves are the fastest seismic waves and can travel through solid, liquid, and gas. 
• They cause a back-and-forth motion of the particles in the material they pass through. 

Answer: B. Insulator

Explanation: Static electricity is the build-up of electric charge on a surface. This occurs when electrons are transferred from one surface to another, resulting in one surface becoming negatively charged and the other becoming positively charged. However, for this to occur, the surface must be able to hold onto the charge.

• Materials that hold on to the charge and do not allow it to flow through them easily are called insulators. 
• Examples of insulators include rubber, plastic, glass, and air. 
• These materials can be charged with static electricity because they do not allow the charge to flow through them easily.
• In contrast, conductors are materials that allow electric charge to flow through them easily. 
• Examples of conductors include metals like copper and aluminum. 
• These materials do not hold on to electric charge and therefore cannot be charged with static electricity.

Therefore, the correct answer is B. Insulator.

Answer: B) Electroscope

Explanation: An electroscope is a device used to test whether an object is carrying charge or not. It works by using the principles of electrostatics. 

• An electroscope consists of a metal rod with a metal ball attached to the top. 
• Inside the metal rod, there are two thin metal leaves that are separated from each other. 
• When the metal ball of the electroscope is touched by an object that is carrying a charge, the charge is transferred to the metal ball and then to the metal leaves. 
• The like charges on the metal leaves will cause them to repel each other and stand apart, indicating that the object is carrying a charge.

Option A) Oscilloscope is an electronic test instrument that is used to observe and measure electrical signals.

Option C) Ammeter is a device that is used to measure the current flowing in a circuit.

Option D) Voltmeter is a device that is used to measure the voltage difference between two points in an electrical circuit.

Hence, the correct answer is B) Electroscope.

Answer: C) Earthquake

Explanation: An earthquake is a natural phenomenon that occurs when the tectonic plates in the Earth's crust move or shift, causing a sudden release of energy. 

• This energy release causes the ground to shake and tremble, which can lead to widespread destruction and loss of life. 
• Earthquakes can occur anywhere on the planet but are more common in areas where tectonic plates meet or where there is volcanic activity. 
• Erosion is the process of wearing away the earth's surface by the action of wind, water, or ice. 
• Tectonics refers to the study of the movement and deformation of the Earth's crust. 
• Volcanism is the phenomenon of the eruption of molten rock and ash from a volcano.

Answer: A) Crust

Explanation: The outermost layer of the earth is called the crust. It is the thinnest layer and ranges from 5-70 kilometres in thickness. 

• The crust is composed of a variety of rocks such as granite, basalt, and sandstone. 
• It is also home to many living organisms and is the layer that we live on. 
• The mantle is the layer below the crust, and the core is the centre of the earth. 
• The lithosphere is a term used to describe the crust and the uppermost part of the mantle together.

Answer: C) The point on the Earth's surface directly above the focus of the earthquake

Explanation: The focus of an earthquake is the point where the energy is released and the earthquake originates. 

• The epicentre is the point on the Earth's surface directly above the focus of the earthquake. 
• This is the point where the earthquake is usually felt the strongest, but it is not necessarily the point where the earthquake is the strongest. 
• The strength of an earthquake decreases as you move away from the epicentre. 
• Therefore, the epicentre is a very important point in determining the severity of an earthquake and is often used to locate the earthquake on a map.

Answer: C) Air is a good conductor during lightning.

Explanation: During lightning, the air surrounding the electrical discharge becomes ionized and can conduct electricity. 

• The sudden discharge of electricity through the air causes a rapid expansion of the air which creates a shock wave, producing the characteristic sound of thunder. 
• In fact, lightning is a prime example of the fact that air is not always an insulator and can become a good conductor under certain conditions. 
• Therefore, the correct answer is C) Air is a good conductor during lightning.

Answer: B. Loose

Explanation: When the wires become loose, they may come in contact with each other or with the electric pole, which can cause sparks to be seen. This is a dangerous situation as it can cause a short circuit or even a fire. Therefore, it is important to regularly check and maintain the wires to ensure they are properly tightened and secured.

Answer: C) Coulomb

Explanation: Electric charge is the fundamental property of matter that can either be positive or negative. The unit used to measure electric charge is the Coulomb (C), which is defined as the amount of charge that flows through a conductor when one Ampere (A) of current flows for one second. 

• The Coulomb is a derived unit of the SI system, and it is equivalent to the charge of 6.24 x 1018 electrons. 
• The other options listed in the MCQ, namely Newton, Joule, and Watt, are all units of force, energy, and power, respectively, and are not related to the measurement of electric charge.

Answer: C) Tsunami

Explanation: An earthquake under the ocean can cause a tsunami. A tsunami is a series of ocean waves with very long wavelengths (typically several hundred kilometres) caused by large-scale disturbances of the ocean, such as earthquakes, volcanic eruptions, or landslides. 

• When an earthquake occurs beneath the ocean, it can cause the seafloor to move abruptly.
• This in turn generates large waves that can travel across the ocean at great speeds.
• It eventually reaches the coastlines and causes devastating damage to buildings, infrastructure, and people. 
• Therefore, it is important to be aware of the potential for tsunamis in areas prone to earthquakes and take appropriate measures to minimize the risks.

Answer: C) Static

Explanation: When two objects are rubbed against each other, the friction between them can cause the transfer of electrons from one object to another, resulting in the buildup of electrical charges. 

• These charges remain stationary on the surface of the objects and do not flow through a conductor, hence they are called static electricity. 
• This type of electricity is commonly observed in our daily lives, such as when we comb our hair, rub a balloon against our clothes, or shuffle our feet on a carpet, resulting in static shocks.