# General Science Physics Questions and Answers – Nobel Prize Winners in Physics (Updated)

## General Science Questions and Answers – Physics

• What is the unit of work? – Joule
• Light Year is the unit for? – Distance
• Lumen is the unit for? – Luminous Flux
• Marie Curie actually coined the term? – Radioactivity
• What physical amount is obtained by the ratio of momentum and velocity of matter? – Mass
• Swimming in water is possible due to which law of motion of Newton? – Third Rule
• On what principle is the functioning of a rocket based? – Momentum Conservation
• If the horse starts moving suddenly, the reason for the fall of the cavalry is – Relaxation Inertia
• For cleaning the carpet, if it is beaten with a stick, then what rule applies in it? – Newton’s first Law of Motion or Law of Inertia
• How much of the iceberg does it float above the surface of the sea? – 1/10
• Which is produced to convert solar energy using light voltaic cell? – Optical Energy
• The use of hydraulic brakes in automated vehicles is virtually a direct application of which rule? – Pascal's law
• When milk is strongly churned, what causes the cream to separate from it? – Centrifugal Force
• The jet engine works on the principle of protection of – Linear momentum
• What is the approximate height of a synchronous satellite from the earth's surface? – 36,000 KM
• How much of the Earth's gravity is closest to the Moon's gravity? – 1/6
• What causes the droplet to become spherical? – Surface Tension
• Why do small pieces of camphor dance on the surface of water? – Due to Surface Tension
• The iron needle sinks in the water but the ship floats. On what principle is this based? – Archimedes' Theory
• What is the law of Archimedes related to? – Rule of Flotation

UPSC IAS Exam Prep and Guide

Prepare for UPSC IAS, Civil Services, GK and Current Affairs

More than 5000+ detailed question and answers

• Who propounded the universal law of gravity? – Newton
• Which is the correct value of the gravity of the working earth on a body of 1 Kg mass? – 9.8 N
• How many watts is equal to one horsepower (HP)? – 746 watts
• Why does an iron needle float on the surface of water? – Due to page tension
• At what angle should a ball be thrown horizontally so that it can cover the maximum horizontal distance? – 45॰
• Who had told before Newton that all things are gravitated towards Earth? – Brahmagupta
• At what angle should a cricket ball be hit to reach the maximum distance? – 45॰ angle to horizontal
• Heat is a type of energy that can be converted into work. Who gave the first direct evidence of this? – Rumford
• Which scientist first rubbed and melted two pieces of ice? – Davy
• For what reason can the temperature of boiling water in a steam engine be high? – High pressure inside boiler
• On what principle is a Thermo Couple Thermometer based? – On the effect of Seebeck
• On which principle is the Total Radiation Pyrometer based? – Stephen's Rule
• The temperature of distant objects like sun etc. is measured by which thermometer? – Full Radiation Thermometer
• At what temperature will the reading be the same in Celsius and Fahrenheit thermometers? – 40॰
• To what degree will the 0° F scale of the Celsius scale be equal to? – 32॰
• The human body temperature is 98.6° C. How much would it be on the Celsius scale? – 37॰C
• Approximately how much of the energy expended in tube light is converted into light? – 60–70ø
• Who invented lightning conductor? – Benjamin Franklin
• What is the grade of the result of the electrical resistance of the human body dry? – 106 ohm
• Which metal is used to generate electricity? – Uranium
• Which is used to measure very short time intervals accurately? – Atomic clocks
• If a man has a temperature of 60॰C, what will be his temperature in Fahrenheit? – 140॰F
• At what temperature is the density of water maximum? – 4॰C
• Why do bicycle tubes explode most of the summer? – The tube bursts due to heat.
• The surface water of a lake is just about to freeze. What will be the temperature of the water in the lower level of the lake? – 4॰C
• In which method of transmission of heat, molecules of matter do not move from one place to another by themselves? – Driving
• By which method does heat transfer to liquids and gases? – Convection
• What type of communication medium does the heat of the Sun come to Earth? – Radiation
• In which method of heat transfer is the medium not necessary? – Radiation
• Which is the method of heat transmission in which the particles of the medium do not move? – Radiation

• What is the transmission of heat through molecular composition? – Convection
• Which part of sun radiation heats up the solar cooker? – Infrared Rays
• Which color combination is most appropriate to avoid sunlight? – Black above, white down
• By which method the thermos flask walls are smeared to minimize heat transfer? – Radiation
• What is the effect of melting point on mixing of waste? – Decreases
• Where will the rice take longer to cook? – Mount Everest
• What is the process of converting a liquid into vapor before its boiling point? – Evaporation
• The concept of internal energy resembles which law of thermodynamics? – First rule
• Which concept confirms the first law of thermodynamics? – Energy Conservation
• At which point is the Fahrenheit temperature twice the centigrade temperature? – 160॰F
• On what does the specific heat of an object depend? – On the mass of the body
• Which temperature measurement in Celsius is equal to 300 Gy? – 27॰C
• Whose radiation can a black body absorb? – High wavelength only
• In winter, what kind of weather do we feel colder? – Clear weather
• Due to which action in the pot of water, water remains cold? – Evaporation
• Who first generated parasitic waves by whistling? – Galton
• Which is used in cleaning the internal parts of aircraft? – Ultrasonic wave
• In what frequency range does a person experience sound vibrations? – 20–20,000 Hz
• Which sound symptoms cause a sound to be thick (Shrill)? – Pitch
• Which one causes the most noise pollution? – Flying the plane
• Which process does not occur in both light and sound? – Polarization
• How long does the effect of sound stay in the human ear? – 1/10 second
• What causes sound waves to generate resonance? – Reflection
• How far from a reflective plane should a person be able to hear their resonance? – 56 feet
• On what principle does a stethoscope sound? – Reflection
• The whistle frequency or sharpness of the approaching train increases, due to which event? – Dappler Effect
• Which type of wave is used in the night vision device? – Infrared Wave
• A jet aircraft is flying in the air at a velocity of 2 Mach. When the velocity of sound is 332 m/s. If so, how much is the speed of the aircraft? – 664 m/s
• Which medium will have the maximum speed of sound at a temperature of about 20॰C? – Iron
• A biological method that uses altruistic sound? – Sonography

• What is the device that is used for identifying and treating sound waves? – Sonar
• What kind of wave is a light wave? – Transverse Wave
• The wave theory of light was established by – Hygens
• On the basis of which phenomena is the light waves transverse confirmed? – Polarization
• Who discovered the electromagnetic form of light? – Maxwell
• Who first showed that light waves diffract? – Gramaldi
• Which phenomena do not occur in both light and sound? – Polarization
• Which theory confirms the waveform of light? – Theory of Interpretation
• Approximately how long does it take for light to reach the Earth from the moon? – 1 second
• How long does it take for sunlight to reach the earth? – 8 minutes 16.6 seconds
• What is the speed of light in air? – 3108 m/s
• Which part of the sun is visible at the time of solar eclipse? – Kirit (Corona)
• For what reason does a coin in a vessel filled with water appear to be slightly raised? – Due to refraction of light
• A stick immersed in water appears to be bent due to which behavior? – Refraction of light
• What makes the sky look blue? – Scattering
• What causes red color in the sky at sunrise and sunset? – Scattering
• What color deflection is more in the rainbow? – Purple
• Why does dry sand appear shiny? – The reason for this is reflection.
• Which one mirror is used to make periscope? – Plane mirror
• The making of bright colors in thin foam of soap is the result of which phenomenon? – Multiple reflections and deviations
• What type of mirror is used in automobile to see the back side traffic? – Convex
• What type of mirror is used in the headlights of vehicles? – Reflective mirror
• What type of mirror should be used to see the traffic behind you while driving a car? – North Mirror
• What image is formed on the retina of the human eye? – Real and Reverse
• If a person stands between two plane mirrors which are inclined at 60॰ angle, then how many images will he see? – 5
• We receive sunlight on the surface of the earth. What type of beam are these lights? – Parallel
• Whose unit is the diopter? – Lens Capacity
• How many colors of white light are made of? – 7
• Which color has maximum wavelength? – Red
• How many colors does the sun's rays have? – 7

• If the atmosphere is not there, what color will the sky appear from the earth? – Black
• Which part of the photographic camera acts like the retina of the eye? – Film
• What type of lens is used in the camera? – Convex
• On which part of the human eye does the image form? – Retina
• Which part of the eye controls the amount of light entering the eye? – Iris
• Which part of the donor's eye is transplanted into the eye donation? – Cornea
• What is the minimum clear vision distance for a healthy eye? – 25 cm
• If a person cannot see distant things clearly, what will be the fault in his eyes? – Myopia
• Which lens is used in the glasses of a person suffering from vision impairment? – Convex lens
• What does a watch instrument use to look at the fine parts of a watch? – Magnified lenses
• How does the signal flow in fiber optical communication? – Light wave
• Which one of the glass can dissect ultraviolet rays? – Crooks Glass
• Which of the types of light is most rapidly absorbed by the plant? – Blue and Red
• Which waves will be affected when light waves pass through the glass into the air? – Wavelength and velocity only
• Which lens is used to correct near–term defects? – Concave
• What type of image does a concave lens always make? – Virtual Image
• On what principle does the fiber optic used in communication only work? – Full internal reflection of light
• How do we produce white light in the tube? – By heating the fiber
• The speed of light passing through which is minimum? – Glass
• On which date is your shadow the shortest in the afternoon? – 21 June
• Photon is the basic unit / volume of – Light
• What is confirmed by the particle composition of radiation? – Light Electrical Effect
• Which lens should be used to correct impurities? – Cylindrical lens
• By whom is the alternating current replaced by a direct current? – Rectifier
• The element of an electric bulb is made up of – Tungsten
• What is a semiconductor chip used in an integrated circuit made of? – Silicon
• If the electrical resistance of a conventional material falls to zero, what is that substance called? – Semiconductor
• What is a static electrical precipitator used to control? – Air Pollutants
• In which direction does the freely suspended magnetic needle stick? – North to South direction
• Earth is a huge magnet. In which direction does its magnetic field extend? – South to North

• What is the mass number of an element that has two protons, two neutrons and two electrons in an atom? – 4
• By what method is the age of the earth determined? – Uranium Method
• What is the Coolidge tube used to generate? – X-Rays
• What causes a huge amount of energy to explode in a nuclear bomb? – Change of material into energy
• What are impurities added on the basis of its use in semiconductor? – Increase its electrical conductivity
• When arsenic atoms are added to the germanium lattice, what does it become? – External Semiconductor
• Which metal is used to generate electricity? – Uranium
• Who propounded the Krishna Hole theory? – S. Chandrasekhar
• The Nobel Prize began in the name of Alfred Nobel, who invented? – Dynamite
• Who invented the airplane at the beginning of this century? – Wright Brothers
• Who invented the electron microscope? – Knoll and Ruska
• What equipment is used by medical doctors / professionals? – Stethoscope
• Which device is used to find the position of objects immersed in the ocean? – Sonar
• What is the device used to measure the intensity of the sun's rays? – Hygrometer
• What is the rotation per second of a flywheel measured? – Stroboscope
• Pyrometer is used in measuring? – High Temperature
• What is the coolant pipe used to produce? – X-Rays
• Who invented the electronic computer? – Eckert and Mashalie

## Physics Questions and Solved Examples

Q.1: Nuclear sizes are expressed in a unit named:
A. Angstrom
B. Fermi
C. Newton
D. Tesla
Explanation: 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.

Q.2: It is easier to roll a stone up a sloping road than to lift it vertical upwards because:
A. Work done in rolling is more than in lifting
B. Work done in lifting the stone is equal to rolling it
C. Work done in rolling a stone is less than in lifting it
D. Work done in both is same but the rate of doing work is less in rolling
Answer: C. Work done in rolling a stone is less than in lifting it
Explanation: Let's consider that time taken would be same for moving the stone at height 'h' in both cases.

1st Case: Let the slope of road be at Q°, we have to do work against sine component of Gravitational force.
i.e. mg sinQ and displacement will be h/sinQ
∴ work done = mg sin Q×h/sinQ = mg×h

2nd Case: If we are lifting stone vertically upwards then we have to do work against the Gravitational force on stone i.e. 'mg' and displacement will be equal to h.
∴ work done = mg×h (f×s).

Hence, we can say that, work done in rolling a stone up on a sloping road (Case 1) would be less and much easier to do than to lift it vertically upwards (Case 2).

SSC Exam Test and Preparation

Prepare for SSC CGL, CHSL, SSC MTS, Junior Engineer

More than 1200+ detailed question and answers

Q.3: Mirage is due to:
A. Equal heating of different parts of the atmosphere
B. Unequal heating of different parts of the atmosphere
C. Depletion of ozone layer in the atmosphere
D. Magnetic disturbances in the atmosphere
Answer: B. Unequal heating of different parts of the atmosphere
Explanation: Unequal heating of different layers of atmosphere causes different temperature for different layers and as a result different densities which further adds that the speed of light will be different in these layers.

Mirage – A mirage is a naturally occurring optical phenomenon in which light rays bend to produce a displaced image of distant objects or the sky.

Why this happens? As we know that, layers have different refractive index, i.e., white going higher from the surface. As the layers becomes rearer, the refractive index decreases. The light ray going up from surface after passing each layer of atmosphere bends away from normal (because it passes from denser to rearer medium). At a particular angle, it suffers total internal reflection and comes back to the surface and falls on a person eye, this phenomenon is called as Mirage.

Q.4: Light year is a unit of:
A. Distance
B. Intensity of light
C. Light
D. Time
Explanation: A light year is a unit of distance. It is the distance that light can travel in a year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km.

Q.5: Light from the Sun reaches us in nearly:
A. 3 minutes
B. 4.7 minutes
C. 8.3 minutes
D. 16.2 minutes
Explanation: The sun's light takes about 8.3 minutes to reach the Earth after it has been emitted from the sun's surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 4.15 hours for Neptune.

Q.6: Pa (Pascal) is the unit for:
A. Conductivity
B. Frequency
C. Pressure
D. Thrust
Explanation: The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength. The unit, named after Blaise Pascal, is defined as one newton per square metre.

Q.7: Planets do not twinkle because:
A. They are very far away from the earth resulting in decrease in intensity of light
B. They are nearer to earth and hence we receive a greater amount of light and therefore minor variations in the intensity are not noticeable
C. They emit light of a constant intensity
D. Their distance from the earth does not change with time
Answer: B. They are nearer to earth and hence we receive a greater amount of light and therefore minor variations in the intensity are not noticeable.
Explanation: Seen from space, stars and planets both shine steadily, But seen from Earth, stars twinkle while planets (usually) don’t. Here's why:

Why do Stars twinkle? They’re so far away from Earth that, even through large telescopes, they appear only as pinpoints. And it’s easy for Earth’s atmosphere to disturb the pinpoint light of a star. As a star’s light pierces our atmosphere, each single stream of starlight is refracted – caused to change direction, slightly – by the various temperature and density layers in Earth’s atmosphere. You might think of it as the light traveling a zig-zag path to our eyes, instead of the straight path the light would travel if Earth didn’t have an atmosphere.

Why do Planets don't twinkle but instead shine more steadily? They’re closer to Earth and so appear not as pinpoints, but as tiny disks in our sky. You can see planets as disks if you looked through a telescope, while stars remain pinpoints. The light from these little disks is also refracted by Earth’s atmosphere, as it travels toward our eyes. But – while the light from one edge of a planet’s disk might be forced to “zig” one way – light from the opposite edge of the disk might be “zagging” in an opposite way. The zigs and zags of light from a planetary disk cancel each other out, and that’s why planets appear to shine steadily.
Read more here: Why don't Planets twinkle as Stars do?

Q.8: Metals are good conductors of electricity because:
A. They have high melting point
B. They contain free electrons
C. The atoms are lightly packed
D. All of the above
Answer: B. They contain free electrons
Explanation: Metals are good conductors of electricity, because they have free electrons. These free electrons act as charge carriers in the metallic structure, allowing electric current to flow through the metal. We can also say, metallic bonds are made from a lattice of ions in a 'cloud' of free electrons. These free electrons are responsible for the ability of metals to:
- Conduct electricity
- Conduct heat especially well

Q.9: Out of the following pairs choose the pair in which the physical quantities do not have identical dimension?
A. Impulse and Moment of Force
B. Force and Rate of Change of Linear Momentum
C. Planck's Constant and Angular Momentum
D. Pressure and Young's Modulus
Answer: A. Impulse and moment of force
Explanation: Impulse – Impulse means change in the momentum of a body, i.e., Impulse = Ft = mv – mu
Moment of Force – The turning effect of force about the axis of rotation is called moment of force or torque.
So, they don't have any units; resulting in no dimensions.

Q.10: 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:
A. Acceleration
B. Kinetic energy
C. Momentum
D. Velocity
Explanation: According to Newton's 2nd law, the Rate of Change of Momentum is equal to Force.

Q.11: Lux is the SI unit of:
A. Intensity of Illumination
B. Luminous Efficiency
C. Luminous Flux
D. Luminous Intensity
Explanation: The SI unit of Intensity of Illumination (Illuminance) is Lux. An Illuminance of 1.0 lux is produced by 1.0 lumen of light shining on an area of 1.0 m^2.

Q.12: Moment of inertia is:
A. Vector quantity
B. Scalar quantity
C. Phasor quantity
D. Tensor quantity