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 sentence is correct reason behind the blue color of ocean water?
[A] Water molecules absorb all other colors except blue
[B] Impurities in Sea water reflect the blue light
[C] Water molecules scatter the blue light
[D] None of the above
Show Answer
Correct Answer: C [Water molecules scatter the blue light]
Notes:
Water molecules scatter the blue light by absorbing the light waves and then rapidly re-emitting the light waves in different directions. That is why there are mostly blue wavelengths that are reflected back to our eyes.
2. Which of the following waves can be used to measure the speed of a approaching car?
[A] Light waves
[B] Micro waves
[C] Radio waves
[D] Sound waves
Show Answer
Correct Answer: C [Radio waves]
Notes:
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies as high as 300 gigahertz to as low as 30 hertz. It is used to measure the speed of an approaching car.
3. The term “Isopycnic” is most closely defined by which among the following?
[A] Two places with same atmospheric pressure
[B] Two liquids with same viscosity
[C] Two liquids with same density
[D] Two places with same temperature
Show Answer
Correct Answer: C [Two liquids with same density]
Notes:
The term “Isopycnic” refers to two substances having the same density. It is derived from the Greek words “iso,” meaning equal, and “pycnos,” meaning dense. In scientific contexts, isopycnic conditions are often used in centrifugation techniques to separate particles based on their density, such as in the purification of DNA or proteins.
4. 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.
5. Which of the following is not a valid conservation law of classical Physics?
[A] Law of conservation of energy
[B] Law of conservation of current
[C] Law of conservation of angular momentum
[D] Law of conservation of charge
Show Answer
Correct Answer: B [Law of conservation of current]
Notes:
The following laws are dealt with in the classical physics: 1. Law of conservation of energy 2. Law of conservation of angular momentum 3. Law of conservation of linear momentum 4. Law of conservation of charge
6. Nuclear Reactors are based on which of the following phenomenon?
[A] Magnetic confinement of Plasma
[B] Nuclear Fusion
[C] Controlled Nuclear Fission
[D] None of the above
Show Answer
Correct Answer: C [Controlled Nuclear Fission]
Notes:
Nuclear Reactors uses Controlled Nuclear Fission to generate electricity. A nuclear reactor splits the atoms of nuclear fuel (eg. uranium) to generate energy to turn water into steam to drive turbine generators. Nuclear fission is the splitting of a heavy nucleus into two lighter ones. Fission was discovered in 1938 by the German scientists Otto Hahn, Lise Meitner, and Fritz Strassmann.
7. 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.
8. A projectile will achieve maximum horizontal range at which angle?
[A] 90°
[B] 60°
[C] 45°
[D] 30°
Show Answer
Correct Answer: C [45°]
Notes:
A projectile will achieve maximum horizontal range when it is projected at an angle of 45°. This concept of maximum horizontal range is used by athletes in long jump, javelin throw, cricket ball throw etc
9. Which of these is the cause of Friction?
[A] Roughness of surfaces in contact
[B] Force of adhesion between the molecules of the surfaces in contact
[C] Both a and b
[D] None of the above
Show Answer
Correct Answer: C [Both a and b]
Notes:
Friction is the force that opposes the relative motion between the two surfaces of objects in contact. Friction is caused due to: 1. Roughness of surfaces in contact 2. Force of adhesion between the molecules of the surfaces in contact
10. 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.
