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. If in a closed room , the door of a refrigerator is kept open for some time , the temperature of room will ?
[A] Increase
[B] Decrease
[C] Remains same
[D] First decrease then become stable
Show Answer
Correct Answer: A [Increase]
Notes:
A refrigerator is like a heat engine. It extracts heat from low temperature reservoir and transfer it to high temperature. If a refrigerator’s door is kept open, then room will become hot, because then refrigerator exhaust more heat into the room than earlier.
2. Which among the following kinds of lenses are used to treat Astigmatism?
[A] Convex Lens
[B] Concave Lens
[C] Bifocal Lens
[D] Cylindrical
Show Answer
Correct Answer: D [Cylindrical]
Notes:
Astigmatism is due to imperfect spherical nature of eye lens. The focal length of eye lens is in two orthogonal directions become different so they cannot see objects in two orthogonal directions simultaneously. This defect in direction can be removed by using cylindrical lens in a particular direction.
3. When a tubelight breaks, a cracking sound is produced because ____?
[A] Pressure inside the lamp is less than atmospheric pressure
[B] Pressure inside the lamp is more than atmospheric pressure
[C] The lamp is filled with reactive gases
[D] The lamp is filled with mercury vapour
Show Answer
Correct Answer: A [Pressure inside the lamp is less than atmospheric pressure ]
Notes:
A fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. The pressure inside the lamp is around 0.3% of atmospheric pressure.
4. Which among the following has highest velocity ?
[A] Hurricane
[B] Tornado
[C] Typhoon
[D] Cyclone
Show Answer
Correct Answer: B [Tornado]
Notes:
Tornadoes has the highest velocity and are more devastating compared to other types of cyclones. They generally occur in the pacific ocean.
5. Which of these is in action in the process of a liquid rising in the syringe when the piston is pulled up?
[A] Capillary action
[B] surface tension
[C] atmospheric pressure
[D] cohesive forces
Show Answer
Correct Answer: C [atmospheric pressure]
Notes:
Atmospheric pressure is the force that causes liquid to rise in a syringe when the piston is pulled up. When the syringe is placed with its opening in a liquid and the plunger is pulled up, the air pressure inside the barrel becomes much less than the atmospheric pressure acting on the liquid. Fluids flow from a high pressure area to a low pressure area. Once the pressure inside the syringe is lower than the pressure outside the syringe, the fluid will flow into the syringe.
6. We can hear a whooshing sound when we hold a spiral conch shell near our ears. What is the most likely reason behind this?
[A] The sound we hear is echoing of our blood rushing through the blood vessels of our ear
[B] The sound is generated by air flowing through the shell – in and out
[C] The ambient noise around us resonates inside the shell
[D] None of the reasons mentioned in statements A, B or C is correct
Show Answer
Correct Answer: C [ The ambient noise around us resonates inside the shell]
Notes:
The most likely explanation for the wave-like noise is ambient noise from around us. The seashell that we hold just slightly above our ear captures this noise, which resonates inside the shell.
7. Who among the following discovered X-rays?
[A] Marie Curie
[B] J.J Thomson
[C] W.C Roentgen
[D] James Chadwick
Show Answer
Correct Answer: C [W.C Roentgen]
Notes:
X-rays were discovered by Wilhelm Conrad Roentgen. W.C Roengten discovered X-Rays while actually working on Cathode rays. X-rays is a form of electromagnetic radiation having a wavelength ranging from 0.01 to 10 nanometers and frequencies in the range 30 petahertz to 30 exahertz. Some Uses of X-Rays: The main use of X-rays is in medicine to check for a broken bone inside body. X-rays can also be used to kill cancer cells. X-rays are used at security checks at airports, railway stations etc. to check customers and baggage. X-rays are also used art historians to see if a picture has been painted on top of an older one. X-ray diffraction is also very important in spectroscopy and as a basis for X-ray crystallography.
8. Who among the following gave the Uncertainity principle?
[A] R.A Milkman
[B] Ernset Rutherford
[C] S.N Bose
[D] Werner Heisenberg
Show Answer
Correct Answer: D [Werner Heisenberg]
Notes:
Werner Heisenberg, a german Physicist, discovered the Uncertainity principle. As per the uncertainty principle, we cannot measure the position (x) and the momentum (p) of a particle with absolute precision. The more accurately we know one of these values, the less accurately we know the other. It represnts the effects of wave-particle duality on the properties of subatomic objects.
9. 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.
10. Which of the following branch of Physics deal with study of Atomic Nuclei?
[A] Nuclear Physics
[B] Bio Physics
[C] Atomic Physics
[D] None of the above
Show Answer
Correct Answer: A [Nuclear Physics]
Notes:
Nuclear physics is a branch of physics that deals with the constituents, structure, behaviour and interactions of atomic nuclei. Atomic physics is a branch of physics that deals with the composition of the atom apart from the nucleus
