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 is true about conduction, convection and radiation mode of transfer of heat?
[A] A Medium is required for conduction but not required for convection and radiation
[B] A medium is required for conduction, convection and radiation
[C] A medium is required for conduction and convection but not required for radiation
[D] A medium is not required for conduction and convectio, radiation
Show Answer
Correct Answer: C [A medium is required for conduction and convection but not required for radiation]
Notes:
A medium is required for conduction and convection but not required for radiation. The radiation can occur even in vaccum but not the others. The conduction can travel through solid. The convection process needs liquid and gas.
3. Whenever there are high winds, such as in storms, thin metal roofs on sheds as well as concave roofs on huts are sometimes blown away. Which among the following explains this correctly?
[A] During windstorm , the atmospheric pressure above the roof is very high in comparison to below the roof
[B] During windstorm , the atmospheric pressure above the roof is very low in comparison to below the roof
[C] The high velocity wind exerts tangential force on the roof surface
[D] The high velocity wind exerts vertical force on the roof surface
Show Answer
Correct Answer: B [During windstorm , the atmospheric pressure above the roof is very low in comparison to below the roof]
Notes:
During the storm, the velocity of wind above the roof surface is very high and hence pressure is low. The pressure below the roof is atmospheric which is higher than the pressure of upper surface. Due to this pressure difference, the roof blows.
4. The X-ray crystallography mainly uses which among the following properties of electromagnetic radiation?
[A] Reflection
[B] Diffraction
[C] Interference
[D] Refraction
Show Answer
Correct Answer: B [ Diffraction]
Notes:
X-ray crystallography helps to determine the atomic and molecular structure of a crystal. The crystalline structure performs the diffraction and it causes a beam of incident X-rays to diffract into many specific directions.
5. Which of the following lie in the Tetra hertz frequency?
[A] Visible Light and Infra Red
[B] Infra Red and Microwaves
[C] Microwaves and Radio Waves
[D] Visible Light and Ultraviolet light
Show Answer
Correct Answer: B [ Infra Red and Microwaves]
Notes:
The range of the tera hertz radiation frequency is from roughly 0.1 THz to 10 THz. It is higher than the frequency of radio waves and microwaves, but lower than the frequency of infrared light.
6. A person weighing 80 Kg. is standing on an accurate scale in an elevator. The elevator is slowing down while moving downwards. In this case the scale will read__?
[A] 80 Kg.
[B] Less than 80 Kg
[C] More than 80 Kg
[D] Either less or more than 80 Kg
Show Answer
Correct Answer: C [More than 80 Kg]
Notes:
When the elevator is slowing down while moving downwards, that means there is an acceleration upwards. The gravitational force must be lesser than the normal force. Thus, during slowing down while moving downwards, the normal force on the feet of a passenger is greater than her weight. In this case the scale will read more than 80 kg.
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. What is the force of attraction between any two bodies by virtue of their masses is called?
[A] Electromagnetic Force
[B] Gravitational Force
[C] Centripetal Force
[D] Nuclear Force
Show Answer
Correct Answer: B [Gravitational Force]
Notes:
Gravitational Force is the force of attraction between any two bodies by virtue of their masses. It is a universal force and every object in the universe experiences gravitational force due to every other object.
9. Which of the following is NOT a unit for measuring pressure?
[A] bar
[B] torr
[C] Pascal
[D] shake
Show Answer
Correct Answer: D [ shake ]
Notes:
bar, torr and Pascal are the units used for measuring pressure whereas shake is a unit of time. 1 bar = 105 Pa 1 bar = 760 torr 1 bar = 1 atmospheric pressure Shake is the smallest practical unit of time. 1 shake = 10-8s
10. What is the S.I unit of Pressure Energy?
[A] Nm
[B] Watt
[C] Joule
[D] No units
Show Answer
Correct Answer: C [ Joule ]
Notes:
Joule is the unit of Pressure energy. Pressure energy is the energy stored in a fluid due to the force per unit area applied onto it Pressure energy = Pressure x volume Its dimensional formula is M L2 T-2
