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. 1 femto metre is equal to how many metres?
[A] 10-12
[B] 10-14
[C] 10-15
[D] 1-24
Show Answer
Correct Answer: C [ 10-15 ]
Notes:1 femto metre is equal to 10
-15 metre. Some other metric prefixes are:
- nano = 10-9
- pico = 10-12
- atto = 10-18
- tera = 1012
- peta = 10-15
- exa = 10-18
2. Which of the following is true about displacement of an object?
[A] It is always equal to the distance travelled by the object
[B] It can be less than the distance travelled by the object
[C] It can be greater than the distance travelled by the object
[D] It always less than the distance travelled by the object
Show Answer
Correct Answer: B [It can be less than the distance travelled by the object]
Notes:
The displacement is the shortest distance between the initial and final position of an object in the given time. The displacement of an object is a vector quantity. It can be less than or equal to the distance but can never be greater than the distance travelled by that object
3. Which of these is/are examples of conservation of linear momentum?
[A] Explosion of bomb
[B] Recoiling of a gun
[C] Fight of rockets and jet planes
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:Some examples of conservation of linear momentum:
- Recoiling of a gun
- Explosion of bomb
- Fight of rockets and jet planes
- A man jumping out of a boat to the shore
- A person on a frictionless surface
4. The minimum speed required to put a satellite into a given orbit around earth is known as:
[A] Escape velocity
[B] Orbital velocity
[C] Kinetic velocity
[D] None of the above
Show Answer
Correct Answer: B [Orbital velocity]
Notes:
The minimum speed required to put a satellite into a given orbit around earth is known as Orbital velocity of the satellite. Orbital velocity (v) = (GM/r)1/2 where G= gravitational constant, M= mass of the earth and r = radius of the orbit of the satellite.
5. Which of the following is the orbital velocity of a satellite orbiting very close to the surface of earth?
[A] 7.92 km/s
[B] 9.8 km/s
[C] 11.2 km/s
[D] 14.8 km/s
Show Answer
Correct Answer: A [7.92 km/s]
Notes:
In this case, the radius of the orbit will be nearly equal to the radius of earth. The orbital velocity of a satellite orbiting very close to the surface of earth is 7.92 km/s.
6. If the time of revolution is T in a satellite, then kinetic energy is proportional to which of the following:
[A] T-4/3
[B] T2/3
[C] T-2/3
[D] T-1/3
Show Answer
Correct Answer: C [T-2/3]
Notes:
The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit. So r is inversely proportional to cube root of the square of T. And Kinetic energy is inversely proportional to r. Therefore, K.E is directly proportional to (T)-2/3
7. Who invented mercury barometer?
[A] Blaise Pascal
[B] Daniel Bernoulli
[C] Albert Einstein
[D] Evangelista Torricelli
Show Answer
Correct Answer: D [Evangelista Torricelli]
Notes:
Evangelista Torricelli devised for the first time a method for measuring atmospheric pressure. A long glass tube closed at one end and filled with mercury is inverted into a trough of mercury. This device is known as ‘mercury barometer’.
8. Which of the following is NOT an application of principle of floatation?
[A] Ships
[B] Balloons
[C] Submarines
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
The principle of floatation states that a floating object displaces its own weight of the fluid in which it floats. Some of the applications of the principle of Floatation:- 1. Ships 2. Balloons 3. Submarines
9. Which of the following is equal to the upthrust of the body?
[A] mass of body
[B] weight of liquid
[C] weight of liquid displaced
[D] density of liquid
Show Answer
Correct Answer: C [weight of liquid displaced]
Notes:
Archimedes Principle: when a body is immersed partially or completely in a liquid, it experiences an upthrust, which is equal to the weight of the liquid displaced by the body.
10. What is the difference of pressure between two sides of the liquid surface called as?
[A] Excess Pressure
[B] Surface Pressure
[C] Fluidic Tension
[D] Viscosity
Show Answer
Correct Answer: A [Excess Pressure]
Notes:
In equilibrium the pressure inside a bubble or drop is more than the pressure outside. The difference of pressure between two sides of the liquid surface is called as excess pressure.
