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
1. Which among the following lens is used to correct Presbyopia?
[A] Convex
[B] Concave
[C] Bifocal
[D] Cylindracal
Show Answer
Correct Answer: C [Bifocal]
Notes:
In Presbyopia defect both near and far object are not clearly visible i.e., far point is lesser than infinity and near point greater than 25 cm. This can be removed either by using two separate spectacles one for myopia and other for hypermetropia or by using bifocal lens. It is an old age disease. At old age ciliary muscles lose their elasticity so they can not change the focal length of eye lens effectively and eye losses its power of accommodation
2. The value of acceleration due to gravity is __________?
[A] Minimum at equator and maximum at poles
[B] maximum at equator and minimum at poles
[C] equal at poles and equator
[D] None of the above
Show Answer
Correct Answer: A [Minimum at equator and maximum at poles]
Notes:
The value of acceleration due to gravity is maximum at equator. This is because the distance from the center is minimum at the equator.
3. Ultrasound which is upper limit of human hearing is characterized by which of the following frequencies?
[A] Above 20 KHz
[B] Above 200 KHz
[C] Above 2 KHz
[D] Below 20 KHz
Show Answer
Correct Answer: A [Above 20 KHz]
Notes:
Ultrasound refers to a sound wave with a frequency greater than the upper limit of human hearing, which is generally over 20 kHz. In general, humans can hear sounds with a frequency between 20 Hz and 20 kHz.
4. Which among the following is a correct definition of the Closed Fuel Cycle?
[A] Preparation of fuel and subsequent processes during reactor operation
[B] Closed Fuel Cycle refers to the process of separating the spent fuel
[C] Closed Fuel cycle is the process in which spent fuel is reprocessed
[D] Closed Fuel cycle is the process in which spent fuel is NOT reprocessed
Show Answer
Correct Answer: C [ Closed Fuel cycle is the process in which spent fuel is reprocessed]
Notes:
The nuclear fuel cycle or Nuclear Fuel Chain is the progression of nuclear fuel through a series of differing stages. It has two parts: 1.Front End: It includes the preparation of the fuel and steps in the service period in which the fuel is used during reactor operation. 2.Back End: Which includes the steps to safely manage, contain, and either reprocess or dispose of spent nuclear fuel. When the spent fuel is reprocessed, it is a closed Fuel Cycle. When the spent Fuel is not reprocessed, it is an open fuel Cycle.
5. The Atomic clocks are most reliable time keepers as of now. What gives them such reliability?
[A] Atomic Clocks keep time by the oscillation of the nucleus of an atom and its surrounding electrons
[B] Atomic clocks work on radioactive disintegration of the nuclei in atoms
[C] Atomic clocks work on vibration of atoms when electricity is passed through them
[D] None of them is a correct reason
Show Answer
Correct Answer: A [ Atomic Clocks keep time by the oscillation of the nucleus of an atom and its surrounding electrons]
Notes:
Normal clocks and watches work on either mechanical or electronic control systems. These systems are not very accurate as they can be affected by many factors. On the other hand, atomic clocks keep time by the oscillation of the nucleus of an atom and its surrounding electrons. The mass of the nucleus and the gravity and electrostatic “spring” between the positively charged nucleus and the electrons set the oscillation frequencies. This oscillation is not directly analogous to the time keeping of normal clocks, but both types of clocks use oscillations to keep track of time. Atomic clocks are more reliable time keepers because their oscillations are not subject to change according to environmental factors such as humidity that would decrease the accuracy of normal clocks. A common misconception is that the atomic clock works on radioactive disintegration of the nuclei. These clocks do not keep time according to atomic decay. In quartz clocks, the vibrations of a quartz crystal are controlled and used to measure time. The quartz vibrates at the rate of 32,768 Hz when electricity is passed through it.
6. A pressure cooker on a stove with its lid tightly closed and the whistle in position is an example of:
[A] open system
[B] closed system
[C] isolated system
[D] adiabatic system
Show Answer
Correct Answer: B [ closed system]
Notes:
A pressure cooker on a stove with its lid tightly closed and the whistle in position is an example of a closed-system thermodynamic process. In a closed-system thermodynamic process, the container (in this case, the pressure cooker) is sealed, and there is no exchange of matter with the surroundings. The pressure cooker is designed to be airtight, so no air or steam can escape while it’s cooking. This sealed environment allows for the buildup of pressure and temperature inside the cooker, which, in turn, speeds up the cooking process.
7. When you throw a ball with an angle to the horizontal (projectile); the ball has __:
[A] Uniform velocity in horizontal direction but uniform acceleration in vertical direction
[B] Uniform acceleration in horizontal direction but uniform velocity in vertical direction
[C] Uniform acceleration in both horizontal and vertical directions
[D] Uniform velocity in both horizontal and vertical directions
Show Answer
Correct Answer: A [ Uniform velocity in horizontal direction but uniform acceleration in vertical direction]
Notes:
The motion of a projectile is two dimensional motion consisting of (i) horizontal motion and (ii) vertical motion. Hence, at any instant, the velocity of a projectile has two components (i) horizontal component and (ii) vertical component. The horizontal component remains unchanged throughout the flight as there is no acceleration in horizontal direction. The vertical component is continuously affected by the force of gravity. Thus, the horizontal motion is uniform motion but the vertical motion is uniformly accelerated motion.)
8. Who among the following is credited to work for the unification of electricity, magnetism and optics field of Physics?
[A] James Clerk Maxwell
[B] Michael Faraday
[C] Haris Christian Oersted
[D] Isaac Newton
Show Answer
Correct Answer: A [James Clerk Maxwell]
Notes:
James Clerk Maxwell made the efforts for the unification of electricity, magnetism and optics field of Physics. He showed that light is an electromagnetic wave. James Clerk Maxwell was a Scottish mathematician, physicist and is known best for his mathematical work on electromagnetism and on the behaviour of gases.
9. Which of the following is the largest practical unit of mass?
[A] Slug
[B] a.m.u
[C] Hyperkg
[D] C.S.L
Show Answer
Correct Answer: D [ C.S.L ]
Notes:
The largest practical unit of mass is called as Chandra Shekhar Limit (C.S.L) which is equivalent to 1.4 times the mass of Sun. Chandrasekhar limit is the maximum mass theoretically possible for a stable white dwarf star. This limiting value was named after Indian-born astrophysicist Subrahmanyan Chandrasekhar, who formulated it in 1930. Using Albert Einstein’s special theory of relativity and the principles of quantum physics, Chandrasekhar showed that it is impossible for a white dwarf star, which is supported solely by a degenerate gas of electrons, to be stable if its mass is greater than 1.44 times the mass of the Sun.
10. Which of the following is the unit of Impulse?
[A] N
[B] Ns
[C] N/s
[D] Ns2
Show Answer
Correct Answer: B [ Ns ]
Notes:
The unit of impulse is Ns. Impulse = Force(N) x Time(s) Impulse can be defined as the integral of a force, F, over the time interval, t, for which it acts.
