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. Hydraulic Brakes work on which principle?
[A] Pascal’s Principle
[B] Archimedes Principle
[C] Newton’s Laws
[D] Casini’s Laws
Show Answer
Correct Answer: A [Pascal’s Principle]
Notes:
In 1647 the French scientist Blaise Pascal (1623–1662) discovered that water exerts the same pressure in all directions. This statement is known as Pascal’s Principle.
Pascal’s law states that increase in pressure at a point in the enclosed liquid in equilibrium is transmitted equally in all directions in liquid and to the Walls of the container. The working of hydraulic lift, hydraulic press and hydraulic brakes are based on Pascal’s law.
2. Fermi-Kurie plot is used for the study of which of the following?
[A] Alpha Decay
[B] Beta Decay
[C] Internal Conversion
[D] Cluster Decay
Show Answer
Correct Answer: B [Beta Decay]
Notes:
Fermi–Kurie plot is a graph developed by Franz N. D. Kurie and is used in studying beta decay. In this graph square root of the number of beta particles whose energy lie within a specific range, divided by the Fermi function, is plotted against beta-particle energy.
3. A small quantity of water is placed in a small cavity made in a block of Ice at 0 degree centigrade. Which of the following will happen?
[A] the temperature of water will become zero and it will freeze
[B] the temperature of water will become zero but it will not freeze
[C] the temperature of the water will become zero and it will come out of the cavity
[D] the temperature of the water will become zero and ice will melt to merge with water
Show Answer
Correct Answer: B [the temperature of water will become zero but it will not freeze]
Notes:
When a small quantity of water is placed in a small cavity made in a block of Ice at 0 degree centigrade the temperature of water will become zero but it will not freeze.
4. Two Flat mirrors are placed at an angle of 60° from each other. How many images will be formed of a Candle placed in between them?
[A] 3
[B] 4
[C] 5
[D] 6
Show Answer
Correct Answer: C [5]
Notes:
If two flat mirrors are placed at an angle ø. Then number of images of an object placed between mirrors are = (360/ø) – 1 .
Here ø = 60
So, number of images of candle = (360/60) -1
SO there will be 5 images.
5. 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.
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. 1 femto metre is equal to how many metres?
[A] 10-12
[B] 10-14
[C] 10-15
[D] 1-24
Show Answer
Correct Answer: C [ 10-15 ]
Notes:1 femto metre is equal to 10
-15 metre. Some other metric prefixes are:
- nano = 10-9
- pico = 10-12
- atto = 10-18
- tera = 1012
- peta = 10-15
- exa = 10-18
8. Which of these pairs has the same unit of measurement?
[A] Rate of flow and Acceleration
[B] Impulse and Moment of Force
[C] Rydberg constant and Gas constant
[D] Pressure and Coefficient of Elasticity
Show Answer
Correct Answer: D [ Pressure and Coefficient of Elasticity ]
Notes:
Pressure and Coefficient of Elasticity have the same unit i.e. N m-2 (Newton per metre square) Other important units: Rate of Flow: m3s-1 Acceleration: ms-2 Rydberg constant: 1/m Gas constant: J/K Impulse: Ns Moment of Force: Nm
9. What is the relation between velocity and acceleration at the highest point of projectile path?
[A] both are at an angle of 45° to each other
[B] both are perpendicular to each other
[C] both are at an angle of 180° to each other
[D] None of the above
Show Answer
Correct Answer: B [both are perpendicular to each other]
Notes:
At the highest point of projectile path, the velocity and acceleration are perpendicular to each other. At the highest point of projectile path, the projectile possesses velocity only along the horizontal direction.
10. The centripetal force and centrifugal force are ______:
[A] equal in magnitude and have same direction
[B] unequal in magnitude and have same direction
[C] equal in magnitude and have opposite direction
[D] unequal in magnitude and have opposite direction
Show Answer
Correct Answer: C [equal in magnitude and have opposite direction]
Notes:
The centripetal force and centrifugal force are equal in magnitude and have opposite direction. Centrifugal force can be regarded as the reaction of centripetal force.
