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Physics Quiz - 1, General Knowledge - Current Affairs MCQ


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25 Questions MCQ Test - Physics Quiz - 1, General Knowledge

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Physics Quiz - 1, General Knowledge - Question 1

Radiocarbon is produced in the atmosphere as a result of

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 1
Explanation:

Radiocarbon is produced in the atmosphere as a result of:


A: Collision between fast neutrons and nitrogen nuclei present in the atmosphere
- Fast neutrons, which are released during the process of nuclear reactions, collide with nitrogen nuclei in the atmosphere.
- This collision results in the formation of radiocarbon, also known as carbon-14 (^14C), through the reaction ^14N + ^1n → ^14C + ^1H.
- This process is known as cosmic ray spallation.
B: Action of ultraviolet light from the sun on atmospheric oxygen
- Ultraviolet (UV) light from the sun can interact with atmospheric oxygen (O2) to produce ozone (O3) in the stratosphere.
- However, the production of radiocarbon does not occur through this process.
C: Action of solar radiations, particularly cosmic rays, on carbon dioxide present in the atmosphere
- Solar radiations, including cosmic rays, can interact with carbon dioxide (CO2) molecules in the atmosphere.
- However, this interaction does not directly produce radiocarbon.
D: Lightning discharge in the atmosphere
- Lightning discharge in the atmosphere can produce radiocarbon.
- The high energy associated with lightning can cause nitrogen molecules (N2) to react with oxygen molecules (O2), resulting in the formation of radiocarbon.
- This process is known as nuclear transmutation and occurs at a very low rate.
Answer: A
- Radiocarbon is primarily produced in the atmosphere as a result of the collision between fast neutrons and nitrogen nuclei present in the atmosphere.
- This collision leads to the formation of radiocarbon (^14C) through the reaction ^14N + ^1n → ^14C + ^1H.
Physics Quiz - 1, General Knowledge - Question 2

It is easier to roll a stone up a sloping road than to lift it vertical upwards because

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 2
Explanation:
To explain why it is easier to roll a stone up a sloping road than to lift it vertical upwards, we need to consider the concept of work and the factors involved in each scenario.
1. Work:
Work is defined as the transfer of energy that occurs when a force is applied to an object, and the object is displaced in the direction of the force. In this case, the work done is the effort required to move the stone.
2. Lifting the stone vertically:
When lifting the stone vertically, the force required is equal to the weight of the stone multiplied by the distance over which it is lifted. This is because the force applied is against the force of gravity pulling the stone downwards. The work done in this case is the force applied multiplied by the distance.
3. Rolling the stone up a sloping road:
When rolling the stone up a sloping road, the force required is less than the weight of the stone. This is because the slope of the road helps to reduce the effective weight of the stone. The force required to roll the stone up the slope is equal to the weight of the stone multiplied by the sine of the angle of the slope. The work done in this case is the force applied multiplied by the distance.
4. Comparison:
Now, let's compare the two scenarios:
- The force required to roll the stone up the slope is less than the force required to lift it vertically.
- The work done in rolling the stone up the slope is less than the work done in lifting it vertically.
- Therefore, it is easier to roll a stone up a sloping road than to lift it vertically because the work done in rolling is less than the work done in lifting.
Answer: D. Work done in rolling a stone is less than in lifting it.
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Physics Quiz - 1, General Knowledge - Question 3

Siphon will fail to work if

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 3
Siphon will fail to work if:

  1. The densities of the liquid in the two vessels are equal: In order for a siphon to work, there needs to be a difference in density between the two liquids. If the densities are equal, there will be no movement of the liquid and the siphon will fail.


  2. The level of the liquid in the two vessels are at the same height: For a siphon to work, there needs to be a difference in height between the two vessels. If the liquid levels are the same, there will be no pressure difference to drive the flow and the siphon will fail.


  3. Both its limbs are of unequal length: The longer limb of the siphon needs to be higher than the shorter limb in order for the liquid to flow. If both limbs are of equal length, there will be no height difference and the siphon will fail.


  4. The temperature of the liquids in the two vessels are the same: Temperature affects the density of liquids. If the temperatures of the liquids in the two vessels are the same, their densities will also be the same. Without a density difference, the siphon will fail to work.



Therefore, the correct answer is B: the level of the liquid in the two vessels are at the same height.
Physics Quiz - 1, General Knowledge - Question 4

Large transformers, when used for some time, become very hot and are cooled by circulating oil. The heating of the transformer is due to

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 4
Explanation:
The heating of the transformer is due to a combination of factors, including the heating effect of current and hysteresis loss. Here is a detailed explanation of why these factors contribute to the heating of the transformer:
1. Heating effect of current:
- When current flows through the transformer's windings, it encounters resistance, which results in the generation of heat.
- This is known as the heating effect of current, according to Joule's law, which states that the heat produced is directly proportional to the square of the current and the resistance.
- The resistance of the transformer windings, combined with the high currents flowing through them, leads to significant heat generation.
2. Hysteresis loss:
- Hysteresis loss is caused by the repeated magnetization and demagnetization of the transformer's core as the alternating current passes through it.
- During each cycle, the core experiences a reversal of magnetization, leading to energy losses in the form of heat.
- These losses are due to the inherent characteristics of the magnetic material used in the transformer's core, which has a limited ability to magnetize and demagnetize efficiently.
- Hysteresis loss contributes to the overall heating of the transformer.
3. Cooling with oil:
- Transformers are equipped with oil-filled tanks that circulate the oil to cool the transformer.
- The oil absorbs the heat generated by the transformer and carries it away through convection.
- The hot oil rises to the top of the tank, where it is cooled by contact with the tank walls or cooling fins.
- It then flows back down to the bottom of the tank, completing the cooling cycle.
4. Intense sunlight:
- The option D, intense sunlight at noon, is not a significant factor in the heating of the transformer.
- While sunlight can contribute to the overall ambient temperature, it is not the primary cause of the heating of the transformer.
In conclusion, the heating of large transformers is primarily due to the combination of the heating effect of current and hysteresis loss. The circulating oil helps to dissipate the heat and maintain the transformer's temperature within acceptable limits. The option C, both the heating effect of current and hysteresis loss, is the correct answer.
Physics Quiz - 1, General Knowledge - Question 5

The absorption of ink by blotting paper involves

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 5
The absorption of ink by blotting paper involves:

  • Capillary action phenomenon: Blotting paper has tiny, narrow channels that act as capillaries, allowing the ink to be drawn up through the paper.

  • Diffusion of ink through the blotting paper: The ink molecules move from an area of higher concentration (where the ink is applied) to an area of lower concentration (the blotting paper), spreading and diffusing through the paper.


Explanation:
When ink is applied to blotting paper, several factors come into play that facilitate the absorption process. The key factor is capillary action, which is the ability of a liquid to move through narrow spaces. In the case of blotting paper, the capillary action is due to the tiny channels present in the paper. These channels create a network of capillaries that draw the ink into the paper.
Once the ink is in contact with the blotting paper, diffusion takes place. Diffusion is the process by which particles or molecules move from an area of higher concentration to an area of lower concentration. In this case, the ink molecules move from the area where the ink is applied (higher concentration) to the blotting paper (lower concentration), spreading and diffusing through the paper.
This combination of capillary action and diffusion allows the ink to be effectively absorbed by the blotting paper, resulting in the ink being pulled into the paper and away from the surface where it was originally applied.
Physics Quiz - 1, General Knowledge - Question 6

Nuclear sizes are expressed in a unit named

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 6

Fermi - A unit of length equal to 10-15 meter (one femtometer), used in nuclear physics. It is similar to the diameter of a proton.

Physics Quiz - 1, General Knowledge - Question 7

Light year is a unit of

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 7
Light year is a unit of:
Distance:
- A light year is a unit of distance used in astronomy to measure vast distances in space.
- It is defined as the distance that light travels in one year in a vacuum.
- Light travels at a speed of approximately 299,792 kilometers per second (or about 186,282 miles per second) in a vacuum.
- In one year, light can cover a distance of about 9.461 trillion kilometers (or about 5.879 trillion miles).
Explanation:
- The concept of a light year helps astronomers to express and understand the enormous distances between celestial objects.
- Since light travels at a finite speed, it takes time for light to travel from one point to another in space.
- The distance light travels in a year is a convenient unit to measure these large distances.
- For example, it takes about 8 minutes and 20 seconds for light from the Sun to reach Earth, so the distance between the Sun and Earth is about 8 light minutes.
- Similarly, the distance between stars, galaxies, and other astronomical objects can be expressed in light years to give a sense of their vastness.
- It is important to note that a light year is a measure of distance, not time. It represents how far light can travel in one year, rather than a specific duration of time.
Conclusion:
- The correct answer is B: distance.
Physics Quiz - 1, General Knowledge - Question 8

Mirage is due to

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 8
Explanation:
The phenomenon of mirage is caused by the unequal heating of different parts of the atmosphere. Here is a detailed explanation:
Unequal Heating:
- When sunlight passes through the Earth's atmosphere, it heats up the air near the surface.
- However, the heating is not uniform, and different parts of the atmosphere may be heated differently.
- This uneven heating creates variations in temperature and refractive index in the air layers.
Refraction of Light:
- Light travels in straight lines, but when it passes from one medium to another with a different refractive index, its path bends. This is known as refraction.
- Mirage occurs due to the refraction of light as it passes through layers of air with different temperatures and refractive indices.
Temperature Inversions:
- In certain atmospheric conditions, temperature inversions can occur. This means that the temperature increases with height instead of decreasing, as it normally does in the troposphere.
- Temperature inversions can cause light rays to bend more sharply, leading to the formation of mirages.
Formation of Mirage:
- When light from a distant object passes through layers of air with different temperatures and refractive indices, it undergoes refraction.
- The bending of light can create an optical illusion, making the object appear displaced or distorted.
- This displacement or distortion is what we perceive as a mirage.
Types of Mirage:
- There are different types of mirages, such as inferior mirages and superior mirages, depending on the specific atmospheric conditions and the angle at which the light is bent.
In conclusion, mirages are caused by the unequal heating of different parts of the atmosphere, which creates variations in temperature and refractive index. When light passes through these layers of air, it undergoes refraction, creating an optical illusion that we perceive as a mirage.
Physics Quiz - 1, General Knowledge - Question 9

Light from the Sun reaches us in nearly

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 9
Light from the Sun reaches us in nearly 8 minutes.
Explanation:
- The distance between the Earth and the Sun is approximately 93 million miles (150 million kilometers).
- Light travels at a speed of about 186,282 miles per second (299,792 kilometers per second).
- To calculate the time it takes for light to reach us from the Sun, we can divide the distance by the speed of light.
- Dividing 93 million miles by 186,282 miles per second gives us approximately 498.65 seconds.
- Converting seconds to minutes, we get approximately 8.31 minutes.
- Therefore, light from the Sun takes nearly 8 minutes to reach us on Earth.
Summary:
- The distance between the Earth and the Sun is 93 million miles.
- Light travels at a speed of 186,282 miles per second.
- Dividing the distance by the speed of light gives us approximately 8.31 minutes.
- Therefore, light from the Sun reaches us in nearly 8 minutes.
Physics Quiz - 1, General Knowledge - Question 10

Stars appears to move from east to west because

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 10
Explanation:
Why do stars appear to move from east to west?
The apparent motion of stars from east to west is due to the rotation of the Earth. Here's a detailed explanation:
1. Earth's Rotation:
- The Earth rotates on its axis, which takes approximately 24 hours to complete one full rotation.
- This rotation causes the Sun, Moon, and stars to appear to move across the sky from east to west.
2. Earth's Axis and Celestial Sphere:
- The Earth's axis is an imaginary line passing through the North and South poles.
- The celestial sphere is an imaginary sphere that surrounds the Earth, with the stars seemingly fixed on its surface.
- As the Earth rotates, the celestial sphere appears to rotate in the opposite direction.
3. Observing Stars:
- When we observe the stars, we are essentially observing their positions relative to the celestial sphere.
- Due to the Earth's rotation, the stars appear to move from east to west across the sky over the course of a night.
4. Apparent Motion:
- The apparent motion of the stars is an illusion caused by the rotation of the Earth.
- In reality, the stars are relatively stationary in space, and it is the Earth's rotation that gives the impression of their movement.
Conclusion:
The stars appear to move from east to west because of the Earth's rotation. This rotation causes the celestial sphere and the stars on it to appear to move across the sky.
Physics Quiz - 1, General Knowledge - Question 11

Pa(Pascal) is the unit for

Physics Quiz - 1, General Knowledge - Question 12

Planets do not twinkle because

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 12
Planets do not twinkle because:
A: They emit light of a constant intensity
- Planets do not emit their own light, they reflect the light from the Sun.
- The reflected light from planets is relatively constant in intensity.
B: Their distance from the Earth does not change with time
- The distance between planets and the Earth does change over time due to their elliptical orbits.
- However, this change in distance is not significant enough to cause noticeable twinkling.
C: They are very far away from the Earth resulting in a decrease in intensity of light
- While planets are indeed far away, their distance does not directly affect the twinkling phenomenon.
- Twinkling is caused by the Earth's atmosphere and its effects on the light passing through it.
D: They are nearer to the Earth and hence we receive a greater amount of light, and therefore, minor variations in the intensity are not noticeable
- The closer a celestial object is to the Earth, the less its light is affected by atmospheric conditions.
- Planets are relatively close compared to stars, so the minor variations in their light intensity are not noticeable as they are not significantly distorted by the Earth's atmosphere.
In conclusion, the correct answer is option D: Planets do not twinkle because they are nearer to the Earth, and we receive a greater amount of light from them. The minor variations in their light intensity are not noticeable due to their proximity and the relatively stable conditions of the Earth's atmosphere.
Physics Quiz - 1, General Knowledge - Question 13

Metals are good conductors of electricity because

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 13
Metals are good conductors of electricity because of the following reasons:
1. Presence of Free Electrons:
- Metals have a unique atomic structure where the outermost electrons of their atoms are loosely bound.
- This allows the outermost electrons to move freely within the metal lattice, creating a sea of delocalized electrons.
- These free electrons are not associated with any particular atom and are able to move throughout the metal.
- The presence of these free electrons facilitates the flow of electric current in metals.
2. Lightly Packed Atoms:
- The atoms in metals are arranged in a closely packed structure.
- The atoms have a relatively large number of available valence electrons.
- These valence electrons are free to move within the lattice due to weak interatomic forces.
- The loosely held electrons make it easier for electric charges to flow through the metal.
3. High Melting Point:
- While a high melting point is not the sole reason for metals being good conductors of electricity, it is a contributing factor.
- Metals generally have high melting points due to the strong metallic bonding between atoms.
- This high melting point ensures that metals remain in their solid state at normal operating temperatures, allowing them to conduct electricity effectively.
Therefore, the correct answer is option A: metals are good conductors of electricity because they contain free electrons.
Physics Quiz - 1, General Knowledge - Question 14

Let a thin capillary tube be replaced with another tube of insufficient length then, we find water

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 14
Explanation:
When a thin capillary tube is replaced with another tube of insufficient length, the following observations can be made:
1. Surface tension: Capillary rise in a tube occurs due to the surface tension of the liquid (in this case, water) trying to minimize its surface area. When the tube is long enough, the surface tension pulls the water up, creating a meniscus.
2. Insufficient length: When the replacement tube is of insufficient length, it means that the tube does not have enough surface area for the surface tension to act upon. As a result, the capillary rise of water cannot occur.
3. Gravity: Gravity also plays a role in determining the height to which water can rise in a capillary tube. If the length of the replacement tube is not long enough, gravity will overcome the surface tension, preventing the water from rising.
4. Water level: In the case of a replacement tube of insufficient length, the water level in the tube will remain at the same level as the surrounding water.
Therefore, the correct answer is B: The water will not rise because the replacement tube does not provide enough surface area for surface tension to act upon, and gravity overcomes the surface tension.
Physics Quiz - 1, General Knowledge - Question 15

Out of the following pairs, choose the pair in which the physical quantities do not have identical dimension?

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 15

To determine which pair of physical quantities does not have identical dimensions, we need to compare their units.
Let's analyze each pair:
A: Pressure and Young's modulus
- Pressure is measured in units of force divided by area, such as pascals (Pa) or N/m^2.
- Young's modulus is measured in units of force divided by area, such as pascals (Pa) or N/m^2.
- Both pressure and Young's modulus have the same dimensions and units, so they have identical dimensions.
B: Planck's constant and Angular momentum
- Planck's constant is measured in units of energy multiplied by time, such as joule-seconds (J·s).
- Angular momentum is measured in units of mass multiplied by length squared divided by time, such as kg·m^2/s.
- Planck's constant and angular momentum have different dimensions and units, so they do not have identical dimensions.
C: Impulse and moment of force
- Impulse is measured in units of force multiplied by time, such as newton-seconds (N·s).
- Moment of force (also known as torque) is measured in units of force multiplied by length, such as newton-meters (N·m).
- Impulse and moment of force have different dimensions and units, so they do not have identical dimensions.
D: Force and rate of change of linear momentum
- Force is measured in units of mass multiplied by length divided by time squared, such as newtons (N).
- Rate of change of linear momentum is measured in units of mass multiplied by length divided by time squared, such as newtons (N).
- Both force and rate of change of linear momentum have the same dimensions and units, so they have identical dimensions.
Therefore, the pair in which the physical quantities do not have identical dimensions is C: Impulse and moment of force.
Physics Quiz - 1, General Knowledge - Question 16

If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 16

When two bodies of different masses are acted upon by the same force for the same time, they will acquire the same momentum. Here's a detailed explanation of why momentum is the correct answer:
1. Force and acceleration:
- Force (F) is defined as the rate of change of momentum. Mathematically, F = ma, where m is the mass of the body and a is the acceleration.
- Since the force acting on both bodies is the same, their accelerations will be different due to the difference in mass. The larger mass will have a smaller acceleration, and the smaller mass will have a larger acceleration.
2. Relationship between force, mass, and acceleration:
- According to Newton's second law of motion, the force acting on an object is directly proportional to its mass and acceleration. Mathematically, F = ma.
- Since the force and time are the same for both bodies, the product of mass and acceleration will be the same for both bodies as well.
3. Momentum:
- Momentum (p) is defined as the product of mass and velocity. Mathematically, p = mv, where m is the mass of the body and v is the velocity.
- Since the product of mass and acceleration is the same for both bodies, and the time is the same, it implies that the product of mass and velocity will also be the same for both bodies.
- Therefore, both bodies will acquire the same momentum.
In conclusion, when two bodies of different masses, initially at rest, are acted upon by the same force for the same time, they will acquire the same momentum.
Physics Quiz - 1, General Knowledge - Question 17

Pick out the scalar quantity

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 17
Scalar Quantity

  • Force: Force is a vector quantity as it has both magnitude and direction. It is represented by an arrow in a specific direction.

  • Pressure: Pressure is a scalar quantity as it only has magnitude and no specific direction. It is defined as the force applied per unit area.

  • Velocity: Velocity is a vector quantity as it has both magnitude and direction. It is defined as the rate of change of displacement with respect to time.

  • Acceleration: Acceleration is a vector quantity as it has both magnitude and direction. It is defined as the rate of change of velocity with respect to time.


Among the given options, pressure is the scalar quantity as it only has magnitude and no specific direction associated with it.

Physics Quiz - 1, General Knowledge - Question 18

Rectifiers are used to convert

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 18
Rectifiers are used to convert

Answer: B. Alternating current to Direct current
Rectifiers are electrical devices used to convert alternating current (AC) into direct current (DC). They are widely used in various electronic and power applications to provide a steady and reliable source of DC power. Here is a detailed explanation of why rectifiers are used to convert AC to DC:
1. Definition of rectifiers
- Rectifiers are electronic devices that convert AC voltage or current into DC voltage or current.
- They typically use diodes as the main component for rectification.
2. Purpose of rectification
- AC voltage or current alternates between positive and negative cycles, constantly changing direction.
- However, many electronic devices and applications require a steady and unidirectional flow of electricity, which is provided by DC power.
- Rectification is necessary to convert the fluctuating AC waveform into a smooth and constant DC waveform.
3. How rectifiers work
- Rectifiers use diodes, which are semiconductor devices that allow current to flow in one direction and block it in the opposite direction.
- During the positive half-cycle of the AC waveform, the diode conducts and allows current to flow in one direction, resulting in positive voltage.
- During the negative half-cycle, the diode blocks the current, preventing it from flowing in the opposite direction, resulting in zero voltage.
- This process effectively converts the AC waveform into a pulsating DC waveform.
4. Types of rectifiers
- There are different types of rectifiers, including half-wave rectifiers, full-wave rectifiers, and bridge rectifiers.
- Half-wave rectifiers use only one diode and are less efficient, as they utilize only half of the AC waveform.
- Full-wave rectifiers use four diodes arranged in a bridge configuration to utilize both halves of the AC waveform, resulting in a smoother DC output.
- Bridge rectifiers are the most commonly used type, as they provide efficient and reliable rectification.
5. Applications of rectifiers
- Rectifiers are used in power supplies to convert the AC voltage from the mains into DC voltage for electronic devices.
- They are also used in battery chargers, inverters, motor drives, and various other applications that require DC power.
In conclusion, rectifiers are essential devices for converting alternating current (AC) into direct current (DC) to meet the requirements of various electronic and power applications. They utilize diodes to rectify the AC waveform and provide a steady and unidirectional flow of DC power.
Physics Quiz - 1, General Knowledge - Question 19

out of the following, which is not emitted by radioactive substance?

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 19

Neutrons are not emitted by radioactive substance.

Physics Quiz - 1, General Knowledge - Question 20

Sound waves in air are

Physics Quiz - 1, General Knowledge - Question 21

Magnetism at the centre of a bar magnet is

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 21
Magnetism at the centre of a bar magnet is zero.
Explanation:
- A bar magnet has two poles, a north pole and a south pole, separated by a magnetic field.
- The magnetic field lines of a bar magnet extend from the north pole to the south pole, creating a magnetic field around the magnet.
- At the centre of the bar magnet, the magnetic field lines from the north pole and the south pole cancel each other out, resulting in a net magnetic field of zero.
- This means that there is no magnetism at the centre of the bar magnet.
- The magnetic field strength is minimum or zero at the centre of the magnet.
- The magnetic field lines curve outwards from the north pole and curve inwards towards the south pole, creating a magnetic field around the magnet.
- The strength of the magnetic field is maximum at the poles of the magnet, where the field lines are concentrated.
- This is why the answer is C: zero.
Physics Quiz - 1, General Knowledge - Question 22

It is more difficult to walk on a sandy road than on a concrete road because

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 22
Friction and Difficulty of Walking on Different Surfaces
The difficulty of walking on different surfaces is determined by the friction between the surface and our feet. Let's analyze why it is more difficult to walk on a sandy road compared to a concrete road.
1. Definition of Friction
- Friction is the force that opposes motion when two surfaces come into contact with each other.
- It is responsible for providing traction and grip, allowing us to walk without slipping.
2. Friction and Walking
- When we walk, our feet push against the ground, creating a force that propels us forward.
- The friction between our feet and the ground resists this forward force, allowing us to maintain balance and move forward.
3. Sand vs. Concrete
- Sand is a loose, granular material made up of small particles, whereas concrete is a solid, rigid material.
- The differences in their physical properties affect the friction between these surfaces and our feet.
4. Friction and Sand
- Sand has a lower coefficient of friction compared to concrete.
- The coefficient of friction is a measure of the frictional force between two surfaces.
- In the case of sand, the loose particles do not provide as much resistance to motion, resulting in less friction between the sand and our feet.
5. Friction and Concrete
- Concrete has a higher coefficient of friction compared to sand.
- The solid and smooth surface of concrete provides more grip and resistance to motion, resulting in higher friction between the concrete and our feet.
6. Difficulty of Walking on Sand
- Due to the lower friction between sand and our feet, it is more difficult to walk on a sandy road.
- The lack of grip and increased sliding effect make it harder to maintain balance and propel ourselves forward efficiently.
Conclusion
In conclusion, walking on a sandy road is more difficult than walking on a concrete road because the friction between sand and our feet is less than that between concrete and our feet. The loose and granular nature of sand reduces the resistance to motion, making it harder to maintain balance and move forward effectively.
Physics Quiz - 1, General Knowledge - Question 23

Find the maximum velocity for the overturn of a car moving on a circular track of radius 100 m. The co-efficient of friction between the road and tyre is 0.2

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 23
Problem: Find the maximum velocity for the overturn of a car moving on a circular track of radius 100 m. The coefficient of friction between the road and tire is 0.2.

To find the maximum velocity for the overturn of a car, we need to consider the maximum centrifugal force that can be exerted on the car before it overturns. This force is given by the product of the car's mass (m), the gravitational acceleration (g), and the coefficient of friction (μ).
1. Calculate the maximum centrifugal force:
- Centripetal force = m * v^2 / r (where v is the velocity and r is the radius of the circular track)
- Centripetal force = m * g * μ (where g is the gravitational acceleration and μ is the coefficient of friction)
- Equating the two expressions for centripetal force, we get:
m * v^2 / r = m * g * μ
v^2 = g * r * μ
v = sqrt(g * r * μ)
2. Substitute the given values:
- Radius (r) = 100 m
- Coefficient of friction (μ) = 0.2
- Gravitational acceleration (g) = 9.8 m/s^2 (approximate value)
- Plug these values into the equation derived in step 1:
v = sqrt(9.8 * 100 * 0.2)
v = sqrt(196)
v ≈ 14 m/s
Conclusion: The maximum velocity for the overturn of the car is approximately 14 m/s. Therefore, the correct answer is option D.
Physics Quiz - 1, General Knowledge - Question 24

Of the following properties of a wave, the one that is independent of the other is its

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 24
Properties of a wave:
- Amplitude
- Velocity
- Wavelength
- Frequency
Independent property:
- Amplitude
Explanation:
- The amplitude of a wave refers to the maximum displacement of particles in a medium from their equilibrium position. It represents the intensity or loudness of the wave.
- The velocity of a wave is the speed at which the wave propagates through a medium. It depends on the properties of the medium, such as density and elasticity, as well as the wavelength and frequency of the wave.
- The wavelength of a wave is the distance between two consecutive points in phase, such as two crests or two troughs. It is inversely proportional to the frequency of the wave.
- The frequency of a wave is the number of complete oscillations or cycles that occur in a given time. It is inversely proportional to the wavelength of the wave.
Conclusion:
- The amplitude of a wave is independent of its velocity, wavelength, and frequency. It solely represents the maximum displacement of particles in a medium and does not depend on the other properties of the wave.
Physics Quiz - 1, General Knowledge - Question 25

An aeroplane is flying horizontally with a velocity of 600 km/h and at a height of 1960 m. When it is vertically at a point A on the ground a bomb is released from it. The bomb strikes the ground at point B. The distance AB is

Detailed Solution for Physics Quiz - 1, General Knowledge - Question 25
The problem states that an airplane is flying horizontally with a velocity of 600 km/h and at a height of 1960 m. A bomb is released from the airplane and strikes the ground at point B. We need to find the distance AB.
To solve this problem, we can use the concept of projectile motion. When the bomb is released, it will have two components of motion: horizontal and vertical.
Horizontal Motion:
- The airplane is flying horizontally, so the horizontal velocity of the bomb will be the same as the airplane's velocity, which is 600 km/h.
- We can convert this velocity to m/s by multiplying it by 1000/3600, which gives us 166.67 m/s.
Vertical Motion:
- The bomb has a vertical velocity of 0 m/s when it is released because it is not moving up or down.
- The bomb is under the influence of gravity, so it will start to accelerate downward with an acceleration of 9.8 m/s².
- The time it takes for the bomb to strike the ground can be found using the equation: h = (1/2)gt², where h is the height (1960 m) and g is the acceleration due to gravity (9.8 m/s²).
- Plugging in the values, we get: 1960 = (1/2)(9.8)t². Solving for t, we find t ≈ 20 s.
Distance AB:
- The horizontal distance traveled by the bomb can be found using the equation: d = vt, where d is the distance, v is the velocity, and t is the time.
- Plugging in the values, we get: d = 166.67 m/s * 20 s. Simplifying, we find d ≈ 3333.33 m.
- Converting this distance to kilometers, we get: 3333.33 m * (1 km/1000 m) = 3.33 km.
Therefore, the distance AB is approximately 3.33 km. So, the answer is C.
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