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. Which of the following is responsible for the fact that Tennis ball bounces higher at high altitudes than in plains?
[A] Low Gravity
[B] High Gravity
[C] Less dense air
[D] Low atmospheric temperature
Show Answer
Correct Answer: C [ Less dense air ]
Notes:
The rarified air at high altitudes gives less resistance to ball.
3. When two mercury drops are brought into contact they form a single bigger drop to get which of the following?
[A] Minimum volume
[B] Minimum surface area
[C] Maximum size
[D] Maximum surface area
Show Answer
Correct Answer: B [Minimum surface area]
Notes:
When two drops of mercury come into contact, they will tend to merge together and form a single drop with a minimum surface area. This is because of the properties of mercury, which is a liquid metal with a high surface tension. The surface tension of a liquid is a measure of its elasticity, and it is determined by the cohesive forces between the molecules of the liquid. In the case of mercury, the high surface tension causes the molecules at the surface of the liquid to be strongly attracted to each other, which results in the formation of a relatively smooth and spherical surface. When two drops of mercury are brought together, the surface tension causes them to merge and form a single drop with the smallest possible surface area. This phenomenon is known as the “minimization of surface area” and it is a common feature of liquids with high surface tension.
4. A piece of Ice was tied with a string to a water bucket’s bottom, and the water bucket was filled with water with ice fully submerged in it. What would be the impact on the level of water when the ice melts away completely?
[A] The level of water will go up
[B] The level of water will go down
[C] The level of water will remain unchanged
[D] The level of water will first increase then come to the previous one
Show Answer
Correct Answer: B [ The level of water will go down]
Notes:
When Ice floats in water, the level of water will remain unchanged when the ice melts away because in this situation, Ice replaced water which is “equal to its weight”. But when the floating ice is taken down in the bottom of the bucket and tied over there with a string, and let melt away, the level of water will come down because now the ice was replacing the water “equal to its volume and Ice has a lower density of water. So The answer of this question is “The level of water will go down”.
5. Which of the following scientific discoveries was made by C.V Raman?
[A] Inelastic scattering of light by molecules
[B] Super Conductivity
[C] Controlled nuclear fission
[D] Cyclotron
Show Answer
Correct Answer: A [Inelastic scattering of light by molecules]
Notes:
C.V Raman discovered the Inelastic scattering of light by molecules in 1928, also named as ‘Raman effect’ Raman scattering is the inelastic scattering of a photon by molecules which are excited to higher vibrational or rotational energy levels. He was the first Indian Physicist to win the Nobel Prize for Physics in 1930. C.V Raman has also been bestowed with the Bharat Ratna Award.
6. Which of the following is the unit of Velocity Gradient?(s=second)
[A] s2
[B] s-1
[C] s
[D] s-2
Show Answer
Correct Answer: B [ s-1 ]
Notes:
The unit of Velocity Gradient is s-1(per second) Velocity Gradient = Velocity/time Velocity gradient shows that how the velocity of a fluid changes between different points within the fluid.
7. What is the relation between velocity and acceleration at the highest point of projectile path?
[A] both are at an angle of 45° to each other
[B] both are perpendicular to each other
[C] both are at an angle of 180° to each other
[D] None of the above
Show Answer
Correct Answer: B [both are perpendicular to each other]
Notes:
At the highest point of projectile path, the velocity and acceleration are perpendicular to each other. At the highest point of projectile path, the projectile possesses velocity only along the horizontal direction.
8. Work done will NOT be zero in which of the following case/cases?
[A] When displacement is zero
[B] When angle between force and displacement vector is zero
[C] When angle between force and displacement vector is 90°
[D] When force is zero
Show Answer
Correct Answer: B [When angle between force and displacement vector is zero]
Notes:
Work done will be zero: 1. When displacement is zero 2. When force is zero 3. When angle between force and displacement vector is zero
9. What is the dimensional formula of Gravitational Potential?
[A] M1 L2 T-2
[B] M1 L-2 T2
[C] M0 L2 T-2
[D] M0 L2 T2
Show Answer
Correct Answer: C [M0 L2 T-2]
Notes:
The dimensional formula of Gravitational Potential is M0 L2 T-2 It is a scalar quantity. S.I. units of Gravitational Potential is J/kg
10. What is the gravitational potential energy for infinite distance?
[A] 0
[B] infinity
[C] 9.8 J
[D] None of the above
Show Answer
Correct Answer: A [0]
Notes:
The gravitational potential energy of a body at a point is defined as the amount of work done in bringing the body from infinity to that point against the gravitational force. U = – GMm/r When r =infinity, then U =0
