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 among the following radiations in the Sunlight causes tanning and sunburn?
[A] Ultraviolet
[B] Visible
[C] Infrared
[D] Micro waves
Show Answer
Correct Answer: A [Ultraviolet]
Notes:
The sunlight that reaches the earth has ultraviolet A and ultraviolet B (UVA and UVB) rays. These ultraviolet rays are the main causes of damage to the skin from the sun. UVA and UVB rays affect the skin’s sensitivity to sun exposure in different ways.
2. 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.
3. Which among the following character of mercury makes it suitable to use in barometers instead of water?
[A] Low density and low vapor pressure
[B] High density and high vapor pressure
[C] Low density and good conductor of heat
[D] High density and low vapor pressure
Show Answer
Correct Answer: D [High density and low vapor pressure]
Notes:
Mercury is typically used in barometers because it is denser and more viscous than water, which makes it more effective at measuring changes in atmospheric pressure. It also has High density and low vapor pressure than water. When atmospheric pressure changes, the mercury in the barometer will either rise or fall in the tube, allowing the barometer to accurately measure the pressure. Additionally, mercury has a lower freezing point and a higher boiling point than water, which makes it less likely to freeze or boil at normal temperatures and therefore more reliable for use in a barometer.
4. You are sitting inside an open vehicle moving with uniform speed. When you throw a stone vertically upwards, the stone will fall__:
[A] Ahead of you
[B] Behind you
[C] Over you
[D] Either ahead or behind of you
Show Answer
Correct Answer: C [ Over you]
Notes:
Uniform speed means no acceleration. If there is no acceleration and the vehicle is moving with uniform speed; the stone will fall over you.
5. Which among the following Radio frequencies are used around the world in air navigational system?
[A] Very Low Frequency (VLF)
[B] Very High Frequency (VHF)
[C] Tetrahertz Radiation (THF)
[D] Ultra High Frequency (UHF)
Show Answer
Correct Answer: B [ Very High Frequency (VHF)]
Notes:
VHF (Very High Frequency) omnidirectional radio range (VOR), is a short-range radio navigation system for aircraft, enabling aircraft to determine their position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons, with a receiver unit. Uses radio frequencies in the very high frequency (VHF) band from 108 to 117.95 MHz. VOR is the standard air navigational system in the world, used by both commercial and general aviation.
6. What is the change in the angular momentum of a system as per the Law of Conservation of Angular momentum, if the total external torque acting is zero?
[A] Remains constant
[B] Becomes zero
[C] Increases exponentially
[D] None of the above
Show Answer
Correct Answer: A [Remains constant]
Notes:
Law of Conservation of Angular Momentum: if the total external torque acting on a system is zero, the angular momentum of a system remains constant. Angular Momentum is the momentum associated with the rotation of an object. Angular Momentum = moment of Inertia X angular Speed
7. What is the maximum height that can be attained by a projectile?
[A] equal to its maximum range
[B] one half of its maximum range
[C] one-fourth of its maximum range
[D] twice of its maximum range
Show Answer
Correct Answer: C [one-fourth of its maximum range]
Notes:
The maximum height that can be attained by a projectile is equal to one-fourth of its maximum range.
8. 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.
9. 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
10. 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
