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. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
1. 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.
2. Fermi-Kurie plot is used for the study of which of the following?
[A] Alpha Decay
[B] Beta Decay
[C] Internal Conversion
[D] Cluster Decay
Show Answer
Correct Answer: B [Beta Decay]
Notes:
Fermi–Kurie plot is a graph developed by Franz N. D. Kurie and is used in studying beta decay. In this graph square root of the number of beta particles whose energy lie within a specific range, divided by the Fermi function, is plotted against beta-particle energy.
3. Which among the following planet / body shows anti-green house effect?
[A] Mars
[B] Venus
[C] Jupiter
[D] Titan
Show Answer
Correct Answer: D [Titan]
Notes:
In our solar System, Mars and Venus show the Green House Effect, but Titan, the largest planet of Saturn and Pluto, shows the opposite phenomena which is called Anti-Green House Effect.
4. One joule of work is said to be done when__:
[A] a force of 1 dyne causes a displacement of 1 cm.
[B] a force of 1 dyne causes a displacement of 1 m.
[C] a force of 1 N causes a displacement of 1 cm.
[D] a force of 1 N causes a displacement of 1 m.
Show Answer
Correct Answer: D [ a force of 1 N causes a displacement of 1 m.]
Notes:
The joule is the unit of energy in the International System of Units. It is equal to the work done on an object when a force of one Newton acts on that object in the direction of the force’s motion through a distance of one meter. One joule of work is said to be done when a force of 1 N causes a displacement of 1 m.
5. Which among the following orbits are more prone to harms of space debris or space Junk in comparison to others?
[A] Polar Sun Synchronous Orbit
[B] Low Earth Orbit
[C] Geosynchronous orbit
[D] Geostationary Orbit
Show Answer
Correct Answer: D [ Geostationary Orbit]
Notes:
Low Earth Orbit (LEO) is more prone to space debris or space junk. This is because space debris is more concentrated in orbits closer to Earth. Most debris is within 2,000 km (1,200 miles) of Earth’s surface.
Space debris orbits the Earth at tremendous speeds, about 15,700 miles per hour (25,265 kph) in low Earth orbit. In the event of a collision, it could cause significant damage to a satellite or spacecraft.
Experts are concerned about the amount of space debris in regions that are too high to benefit from the cleansing effects of Earth’s atmosphere. They believe that if there is too much space junk in orbit, it could result in a chain reaction where more and more objects collide and create new space junk.
6. By how many times are the Electrostatic forces stronger than the Gravitational Forces for a fixed distance?
[A] 102
[B] 1036
[C] 1012
[D] 2
Show Answer
Correct Answer: B [1036]
Notes:
Electrostatic forces are 1036 times stronger than the Gravitational Forces for a fixed distance. Electrostatic forces may be attractive or repulsive depending upon the charges. Electrostatic forces are conservative forces and obey inverse square law.
7. What is the absolute unit of power in c.g.s system?
[A] dyne
[B] erg
[C] watt
[D] erg s-1
Show Answer
Correct Answer: D [erg s-1]
Notes:
Power is defined as the rate of doing work. The absolute unit of power in c.g.s system is erg s-1 The absolute unit of power in S.I system is watt 1 watt = 1 joule/sec 1 kW= 1000 watt 1 h.p = 746 W
8. What happens to the velocity of a light body when it undergoes an elastic collision in one dimension with a very heavy body at rest?
[A] its velocity becomes twice
[B] it rebounds with twice of its own velocity
[C] it rebounds with its own velocity
[D] it stops and comes to rest
Show Answer
Correct Answer: C [it rebounds with its own velocity]
Notes:
A light body rebounds with its own velocity when it undergoes an elastic collision in one dimension with a very heavy body at rest. Note: The heavy body continues to be in rest in this case
9. Which of the following is correct about acceleration due to gravity?
[A] it increases with depth
[B] it decreases with depth
[C] it is independent of depth
[D] None of the above
Show Answer
Correct Answer: B [it decreases with depth]
Notes:
The value of acceleration due to gravity decreases with depth. g0= g(1-d/R) where d is the depth below the centre of the earth.
10. Which of the following statements is correct about the value of acceleration due to gravity (g) in a light and heavy falling body?
[A] the value of g will be greater in the light body
[B] the value of g will be greater in the heavy body
[C] the value of g will be equal in both the bodies
[D] the value of g depends on the mass
Show Answer
Correct Answer: C [the value of g will be equal in both the bodies]
Notes:
Acceleration due to gravity is independent of mass, shape, size etc. of falling body. Therefore, a light and heavy body will have equal acceleration.
