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 of the following statements is incorrect about a Plane Mirror?
[A] The focal length of a plane mirror is infinity
[B] Its optical power is one
[C] It forms a virtual image of a real object
[D] It is used in constructing periscope
Show Answer
Correct Answer: B [Its optical power is one]
Notes:
Second statement is incorrect because the optical power of plane mirror is zero.
2. 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.
3. Which of the following term denotes the internal reaction force per unit area developed as a result of applied external force ?
[A] Stress
[B] Friction
[C] Moment of Inertia
[D] tension
Show Answer
Correct Answer: A [Stress]
Notes:
Stress is the force acting per unit area. It is the internal force reaction per unit area developed as a result of external force.
4. 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.
5. A transition from the solid to gas phase with no intermediate liquid stage is called?
[A] Evaporation
[B] Sublimation
[C] Adsorption
[D] Solid Phase extraction
Show Answer
Correct Answer: B [Sublimation]
Notes:
Sublimation is the process by which a substance transitions from a solid to a gas without passing through a liquid phase. This typically occurs when a substance is heated to a temperature at which its solid form becomes a gas, such as when dry ice (solid carbon dioxide) sublimates and turns into gas. Sublimation can also occur when a substance is exposed to a vacuum, which can cause gases to be drawn out of the substance and turn into a solid. Sublimation is an important process in many scientific and industrial fields, including meteorology, chemistry, and materials science. Camphor is also an example of Sublimation.
6. Which of the following waves is called compression-dilation waves or longitudinal waves?
[A] Primary waves
[B] Secondary waves
[C] Love waves
[D] Rayleigh waves
Show Answer
Correct Answer: A [Primary waves]
Notes:
Primary wave is also called compression-dilation or longitudinal waves. Secondary wave is called transversal wave. Love wave and Rayleigh wave are surface waves. P waves can pass through solid, liquid and gases and are also the fastest among the three main types of waves.
7. Which of the following is NOT correct about Vectors addition?
[A] Vectors addition is associative
[B] Vectors addition is commutative
[C] Vectors of different natures can be added
[D] None of the above
Show Answer
Correct Answer: C [Vectors of different natures can be added]
Notes:
Vectors addition is associative and commutative. But vectors of the same nature alone can be added. Example: a Force vector cannot be added to velocity vector as they are of different nature.
8. The apparent weight of the body becomes zero in which of the following cases in the elevator?
[A] during free fall of a body under gravity
[B] when elevator is accelerating downwards
[C] when elevator is at rest
[D] when elevator is accelerating upwards
Show Answer
Correct Answer: A [during free fall of a body under gravity]
Notes:
The apparent weight of the body becomes zero in an elevator during free fall of a body under gravity. It can be said that the body becomes weightless as the force of reaction between the person and the plane with which he is in contact vanishes.
9. The second law of motion gives us a measure of which of the following physical quantities?
[A] Acceleration
[B] Force
[C] Power
[D] Work done
Show Answer
Correct Answer: B [Force]
Notes:
The second law of motion gives us a measure of force. The product of the mass of the body and the acceleration produced in it gives us the magnitude of force. Force (f) = mass (m) x acceleration (a) Force is a vector quantity and the direction is same as that of acceleration
10. Work done will NOT be zero in which of the following case/cases?
[A] When displacement is zero
[B] When angle between force and displacement vector is zero
[C] When angle between force and displacement vector is 90°
[D] When force is zero
Show Answer
Correct Answer: B [When angle between force and displacement vector is zero]
Notes:
Work done will be zero: 1. When displacement is zero 2. When force is zero 3. When angle between force and displacement vector is zero
