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. What is the use of Venturimeter?
[A] to measure subdivisions of scale
[B] to measure wavelength of radio wave
[C] To measure friction
[D] to measure rate of flow of fluids
Show Answer
Correct Answer: D [to measure rate of flow of fluids]
Notes:
A Venturimeter is the device used to measure rate of flow of fluids. This device is based on the principle of Bernoulli’s Equation.
2. Which among the following defines cohesive force?
[A] the force of attraction acting between the molecules of same material
[B] the force of attraction acting between the molecules of different material
[C] the force of attraction acting between the atoms of same material
[D] None of the above
Show Answer
Correct Answer: A [the force of attraction acting between the molecules of same material]
Notes:
The force of attraction acting between the molecules of same material is known as cohesive force. Cohesive force is the action or property of like molecules sticking together, being mutually attractive.
3. 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.
4. Which among the following provides the centripetal force to an electron circulating around the nucleus?
[A] electrostatic forces of repulsion
[B] electrostatic force of attraction
[C] speed of the electron
[D] nuclear charge
Show Answer
Correct Answer: B [electrostatic force of attraction]
Notes:
The correct answer is “electrostatic force of attraction.” In an atom, electrons are negatively charged and are attracted to the positively charged nucleus due to Coulomb’s law. This attraction provides the necessary centripetal force to keep the electron in a stable orbit around the nucleus. The balance between this electrostatic force and the electron’s inertia allows for stable atomic structures.
5. Which among the following strictly works on the principle of dipole movement of the water molecules?
[A] Refrigerator
[B] Microwave Oven
[C] Air Conditioner
[D] Electric Geyser
Show Answer
Correct Answer: B [Microwave Oven]
Notes:
Microwave Oven strictly works on the principle of dipole movement of water molecule. A microwave oven is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range.
6. A train travels at the speed of 180 km/hr. What is its speed in m/s?
[A] 5 m/s
[B] 30 m/s
[C] 40 m/s
[D] 50 m/s
Show Answer
Correct Answer: D [50 m/s]
Notes:
The speed of the train, given in kilometers per hour, is to be converted to meters per second. We use the conversion formula which states that 1 km/hr is equal to 5/18 m/s. Using the formula, we get (180 x 5)/18, which equals 50 m/s. This conversion is often applied in physics to accurately measure speed or velocity in different units for a variety of calculations, such as computation or comparison of speeds of different objects moving at varying velocities.
7. If the distance between the earth and the sun becomes one-fourth of what it is now, the gravitational force exerted on the earth by the sun would be:
[A] One-fourth of what it is now
[B] One-sixteenth of what it is now
[C] Sixteen times of what it is now
[D] Four times of what it is now
Show Answer
Correct Answer: C [ Sixteen times of what it is now]
Notes:
Gravitational force is inversely proportional to the square of the distance between the bodies.
8. How the brain interprets the frequency of an emitted sound is called its __:
[A] Pitch
[B] Amplitude
[C] Intensity
[D] Timbre
Show Answer
Correct Answer: A [ Pitch]
Notes:
How the brain interprets the frequency of an emitted sound is called the pitch. Researchers have discovered a discrete region of the monkey brain that processes pitch, the relative high and low points of sound, by recognizing a single musical note played by different instruments.
9. Due to which of the following phenomena, the coloured glass appears white when crushed into fine powder?
[A] Total Internal Reflection
[B] Diffraction
[C] Scattering
[D] Refraction
Show Answer
Correct Answer: C [ Scattering]
Notes:
When the glass is crushed into fine powder the light incident is totally scattered without the absorption so due to the composite light crushed glass appears white.
10. 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.
