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 is true about Total Internal Reflection?
[A] A ray passing from rarer to denser medium and not able to pass to denser medium at an angle greater than critical angle
[B] A ray passing from denser to rarer medium and not able to pass to rarer medium at an angle greater than critical angle
[C] A ray passing from either denser to rarer medium or rarer to denser medium and not able to pass any medium at an angle smaller than critical angle
[D] None of the above
Show Answer
Correct Answer: B [A ray passing from denser to rarer medium and not able to pass to rarer medium at an angle greater than critical angle]
Notes:
A ray passing from denser to rarer medium and not able to pass to rarer medium at an angle greater than critical angle. Critical angle is the angle in which the incident ray is 90 degrees to that of the refracted ray.
2. Steam at 100 degree centigrade causes more severe burns. Which of the following phenomena will you use to explain this?
[A] Specific heat
[B] Latent heat
[C] Fusion
[D] Fission
Show Answer
Correct Answer: B [Latent heat]
Notes:
Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. So steam at 100 degree centigrade causes more severe burns.
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. On which of the following Inertia of an object depends ?
[A] Bulk
[B] Size
[C] Shape
[D] Mass
Show Answer
Correct Answer: D [Mass]
Notes:
Inertia is the resistance experienced by an object to any change in its velocity. This includes changes to the object’s speed, or direction of motion. Inertia of rest, Inertia of motion are the examples.
5. Which among the following correctly represents a Parsec?
[A] 0.326 Light Years
[B] 3.261 Light Years
[C] 32.61 Light Years
[D] 3.026 Light Years
Show Answer
Correct Answer: B [3.261 Light Years]
Notes:
One parsec is approximately equal to 31 trillion kilometres (19 trillion miles), or 210,000 astronomical units, and equates to about 3.3 light-years.
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 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. The value of coefficient of limiting friction does not depend on which of the following?
[A] nature of the surfaces in contact
[B] total area of the surfaces in contact
[C] material of the surfaces in contact
[D] All of the above
Show Answer
Correct Answer: B [total area of the surfaces in contact]
Notes:
The coefficient of static friction can be defined as the ratio of the limiting static friction and the normal reaction between the 2 surfaces. The value of coefficient of limiting friction depends: 1. Nature of the surfaces in contact. 2. Material of the surfaces in contact
9. As per the Newton’s second law of motion, what is the relation between the rate of change of linear momentum and the external force applied?
[A] directly proportional
[B] inversely proportional
[C] independent of each other
[D] None of the above
Show Answer
Correct Answer: B [inversely proportional]
Notes:
As per the Newton’s second law of motion, the rate of change of linear momentum of a body is inversely proportional to the external force applied on the body. This change always takes place in the direction of the force applied.
10. The work done in moving a body over a smooth inclined plane does not depend on which of the following?
[A] mass of the body
[B] height of the inclined plane
[C] slope of the inclined plane
[D] All of the above
Show Answer
Correct Answer: C [slope of the inclined plane]
Notes:
The work done in moving a body over a smooth inclined plane does not depend on the slope of the inclined plane. W = mgh in case of smooth inclined plane, where m = mass of the body, g = acceleration due to gravity and h = height of the inclined plane.
