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
11. Which of the following statements about Pressure and Stress is NOT correct?
[A] Pressure is always normal to the area
[B] Pressure is always compressive in nature
[C] Stress can be normal or tangential to the area
[D] Stress is always compressive in nature
Show Answer
Correct Answer: D [Stress is always compressive in nature]
Notes:
Pressure is always normal to the area but Stress can be normal or tangential to the area. Pressure is always compressive in nature but Stress may be compressive or tensile in nature.
12. What is the upward force experienced by a body, when it is immersed in a fluid, known as?
[A] Tangential force
[B] Buoyant force
[C] Centrifugal force
[D] Hydraulic force
Show Answer
Correct Answer: B [Buoyant force]
Notes:
When a body is immersed in a fluid (liquid or gas) it exerts an upward force on that body. This upward force is called up thrust or buoyant force, The whole phenomenon is called as buoyancy.
13. Which is the effect of increase in impurities on the surface tension of the liquid?
[A] It increases
[B] It decreases
[C] It may increase or decrease
[D] No change
Show Answer
Correct Answer: C [It may increase or decrease]
Notes:
The presence of impurities considerably affect the force of surface tension, depending upon the degree of contamination. A highly soluble substance like sodium chloride when dissolved in water, increases the surface tension of water. But the sparingly soluble substances like phenol when dissolved in water, decreases the surface tension of water.
14. Which of these instruments is used for testing the purity of milk?
[A] Hydrometer
[B] Lactometer
[C] Galvanometer
[D] Ammeter
Show Answer
Correct Answer: B [ Lactometer ]
Notes:
Lactometer is used for measuring the relative density of milk and hence testing the purity of milk. It is a specially designed hydrometer.
15. What is the oscillation in which the loss of oscillator is compensated by the supplying energy from an external source known as?
[A] Free oscillation
[B] Maintained oscillation
[C] Forced oscillation
[D] Damped oscillation
Show Answer
Correct Answer: B [Maintained oscillation]
Notes:
The oscillation in which the loss of oscillator is compensated by the supplying energy from an external source are known as maintained oscillation.
16. What are those oscillations whose amplitude goes on decreasing with time are known as?
[A] Damped oscillation
[B] Maintained oscillation
[C] Free oscillation
[D] Forced oscillation
Show Answer
Correct Answer: A [Damped oscillation]
Notes:
The oscillation of a body whose amplitude goes on decreasing with time are defined as damped oscillation. In these oscillation the amplitude of oscillation decreases exponentially due to damping forces like frictional force, viscous force, hystersis etc.
17. What is the relationship between the spring constant k and the spring length in case of spring pendulum?
[A] spring constant is inversely proportional to the spring length
[B] spring constant is directly proportional to the spring length
[C] spring constant is independent of the spring length
[D] spring constant is twice the spring length
Show Answer
Correct Answer: A [spring constant is inversely proportional to the spring length]
Notes:
The spring constant of a spring pendulum is inversely proportional to the spring length.
18. What is the measure of the response of the ear to the sound known as?
[A] Pitch
[B] Intensity
[C] Loudness
[D] Amplitude
Show Answer
Correct Answer: C [Loudness]
Notes:
Loudness is a measure of the response of the ear to the sound. Even when two sounds are of equal intensity, we may hear one as louder than the other simply because our ear detects it better.
19. What is the S.I unit of heat energy?
[A] Joule
[B] Kelvin
[C] Candela
[D] Ampere
Show Answer
Correct Answer: A [Joule]
Notes:
The SI unit of heat energy transferred is expressed in joule (J) while SI unit of temperature is Kelvin (K), and degree Celsius (°C) is a commonly used unit of temperature.
20. On which of the following the molar specific heat capacity of a substance depends?
[A] Nature of the substance
[B] Temperature of the substance
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
The molar specific heat capacity of the substance depends on the nature of the substance and its temperature.
