Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India.
1. Hydraulic Brakes work on which principle?
[A] Pascal’s Principle
[B] Archimedes Principle
[C] Newton’s Laws
[D] Casini’s Laws
Show Answer
Correct Answer: A [Pascal’s Principle]
Notes:
In 1647 the French scientist Blaise Pascal (1623–1662) discovered that water exerts the same pressure in all directions. This statement is known as Pascal’s Principle.
Pascal’s law states that increase in pressure at a point in the enclosed liquid in equilibrium is transmitted equally in all directions in liquid and to the Walls of the container. The working of hydraulic lift, hydraulic press and hydraulic brakes are based on Pascal’s law.
2. What is the use of Venturimeter?
[A] to measure subdivisions of scale
[B] to measure wavelength of radio wave
[C] To measure friction
[D] to measure rate of flow of fluids
Show Answer
Correct Answer: D [to measure rate of flow of fluids]
Notes:
A Venturimeter is the device used to measure rate of flow of fluids. This device is based on the principle of Bernoulli’s Equation.
3. What happens when a ship enters a Sea from a river ?
[A] It rises
[B] It remains at the same level
[C] sinks a little
[D] None of the above
Show Answer
Correct Answer: A [It rises]
Notes:
When a ship enters a sea from a river ,the ship is elevated or uplifted due to the density of sea water and during the buoyant motion of the ship, as it would gain both potential and kinetic energy when rising in the fluid.
4. Edwin Howard Armstrong was an inventor of which of the following technologies?
[A] Television
[B] Compact Discs
[C] FM Radio
[D] Broadband
Show Answer
Correct Answer: C [FM Radio]
Notes:
Edwin Howard Armstrong was an American electrical engineer who developed FM radio and the superheterodyne receiver system. Edwin Howard Armstrong is the “father of FM radio” and was born in 1890.
5. Which frequency range characterizes Ultrasound, that is beyond the upper limit of human auditory perception?
[A] Above 20 KHz
[B] Above 200 KHz
[C] Above 2 KHz
[D] Below 20 KHz
Show Answer
Correct Answer: A [Above 20 KHz]
Notes:
Ultrasound corresponds to sound waves with frequencies exceeding the upper limit of human perceptible sound, generally above 20 kHz. Humans, typically, can perceive sounds ranging between 20 Hz and 20 kHz. Ultrasound, therefore, is beyond the auditory range of humans and is employed in technologies like medical imaging and sonar devices due to its unique properties.
6. Which among the following waves are most commonly used in the Night Vision Devices?
[A] Microwaves
[B] Infra Red Waves
[C] Ultra Violet Waves
[D] Radio Waves
Show Answer
Correct Answer: B [Infra Red Waves]
Notes:
Infrared waves are used in the night vision apparatus such as night vision goggles. Active infrared night-vision combines infrared illumination of spectral range 700–1,000 nm (just below the visible spectrum of the human eye) with CCD cameras sensitive to this light.
7. In which of the following conditions, a Balloon filled with a gas such as Hydrogen will tend to rise up?
[A] If the buoyant force exerted by the air on a balloon is greater than the weight of the balloon
[B] If the buoyant force exerted by the air on a balloon is less than the weight of the balloon
[C] If the buoyant force exerted by the air on a balloon is equal to the weight of the balloon
[D] If the density of the air is greater than the density of the gas filled in balloon
Show Answer
Correct Answer: A [ If the buoyant force exerted by the air on a balloon is greater than the weight of the balloon]
Notes:
A Balloon filled with a gas such as Hydrogen gas is much lighter in weight than the weight of air displaced by it. So the buoyant force exerted by the air on a balloon is greater than the weight of the balloon. The hydrogen gas which is lighter than air enables the balloon to float.
8. What is the time taken by the earth to complete one rotation about its axis with regard to a fixed star?
[A] Sidereal day
[B] Solar day
[C] Shake
[D] Tropical year
Show Answer
Correct Answer: A [Sidereal day]
Notes:
Sidereal day is the time taken by the earth to complete one rotation about its axis w.r.t a fixed star Solar day is the time taken by the earth to complete one rotation about its axis w.r.t the sun. Shake is the smallest practical unit of time 1 shake = 10-8s Tropical year: The year in which there is a total solar eclipse.
9. When one body is actually moving over the surface of other body, the friction is known as:
[A] Kinetic friction
[B] Limiting friction
[C] Static friction
[D] Negative friction
Show Answer
Correct Answer: A [Kinetic friction]
Notes:
When one body is actually moving over the surface of other body, the friction is known as Kinetic friction. It is also known as dynamic friction.
10. An orbital velocity of a satellite does not depend on which of the following?
[A] Radius of the planet
[B] Mass of the planet
[C] Radius of orbit
[D] Mass of the satellite
Show Answer
Correct Answer: D [Mass of the satellite]
Notes:
An orbital velocity of a satellite does not depend on the mass of the satellite. It depends on the mass and radius of the planet around which it is orbiting. Also, it depends on the radius of the orbit or the height of the satellite.
