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. Which of the following statements is incorrect about a Plane Mirror?
[A] The focal length of a plane mirror is infinity
[B] Its optical power is one
[C] It forms a virtual image of a real object
[D] It is used in constructing periscope
Show Answer
Correct Answer: B [Its optical power is one]
Notes:
Second statement is incorrect because the optical power of plane mirror is zero.
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. The value of acceleration due to gravity is __________?
[A] Minimum at equator and maximum at poles
[B] maximum at equator and minimum at poles
[C] equal at poles and equator
[D] None of the above
Show Answer
Correct Answer: A [Minimum at equator and maximum at poles]
Notes:
The value of acceleration due to gravity is maximum at equator. This is because the distance from the center is minimum at the equator.
4. Which of the following waves can be used to measure the speed of a approaching car?
[A] Light waves
[B] Micro waves
[C] Radio waves
[D] Sound waves
Show Answer
Correct Answer: C [Radio waves]
Notes:
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies as high as 300 gigahertz to as low as 30 hertz. It is used to measure the speed of an approaching car.
5. Mach number is a measure of which of the following?
[A] Speed
[B] Heat Transfer
[C] Static Pressure
[D] Volume
Show Answer
Correct Answer: A [Speed]
Notes:
Mach number refers to the ratio of the velocity of a fluid to the velocity of sound in that fluid, named after Ernst Mach (1838–1916), an Austrian physicist and philosopher. Speed of sound is Mach 1 speed.
6. 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.
7. Which among the following is the SI physical unit of dynamic viscosity?
[A] Poise
[B] Pascal-second
[C] Newton-second
[D] Poise-second
Show Answer
Correct Answer: B [Pascal-second]
Notes:
The SI unit for dynamic viscosity η is the Pascal-second (Pa-s). It corresponds to the force (N) per unit area (m2) divided by the rate of shear (s-1).
8. Power of lens is measured in which of the following units?
[A] metre
[B] dioptre
[C] lumen
[D] watt
Show Answer
Correct Answer: B [ dioptre ]
Notes:
Power of lens is measured in dioptre(D). Power of lens = 1/focal length The power of a lens is its ability to bend light. The greater the power the greater the refraction of light.
9. Which of the following is correct about Kinetic energy during the projectile motion?
[A] it is minimum at the point of projection
[B] it is minimum at the highest point
[C] it is maximum at the highest point
[D] it is minimum at the point of reaching the ground
Show Answer
Correct Answer: B [it is minimum at the highest point]
Notes:
The Kinetic energy of an object is maximum at the point of projection or at the point of reaching the ground. It is minimum at the highest point.
10. What is the rate of acceleration produced by 1 dyne force acting on a body of mass 1 gram?
[A] 9.8 m s-2
[B] 1 m s-2
[C] 1 cm s-2
[D] 9.8 cm s-2
Show Answer
Correct Answer: C [1 cm s-2]
Notes:
One dyne force is that much force which produces an acceleration of 1 cm s-2 in a body of mass one gram. 1 dyne = 1 g cm s-2 Also, 1 N = 105 dyne
