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. At which of the following places water shall boil at the lowest temperature?
[A] Kochi
[B] Ooty
[C] Mount Abu
[D] New Delhi
Show Answer
Correct Answer: B [Ooty]
Notes:
This question is related to Antoine equation. Water to get boil, its vapour pressure must reach to its surrounding pressure. In a pressure cooker, it boils at the highest temperature. Elevation of Kochi is 0 m, ooty is 2,486 m, Mount Abu is 1,200 m, New Delhi is 216 m, Shimla is 2,205 m. So comparing all of them, water will boil at lowest temperature at ooty, followed by Shimla, Mount Abu , New Delhi and Kochi. This is because , higher we go lower is the atmospheric pressure and lower is the point where water`s vapour pressure gets equal to the atmospheric pressure.
2. Power of lens is measured in which of the following units?
[A] metre
[B] dioptre
[C] lumen
[D] watt
Show Answer
Correct Answer: B [ dioptre ]
Notes:
Power of lens is measured in dioptre(D). Power of lens = 1/focal length The power of a lens is its ability to bend light. The greater the power the greater the refraction of light.
3. What is the angular acceleration of a body moving with constant angular velocity?
[A] equal to the angular velocity
[B] 1
[C] 0
[D] Can’t be determined
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Correct Answer: C [0]
Notes:
The angular acceleration of a body moving with constant angular velocity is 0. Angular acceleration of an object in circular motion is defined as the time rate of change of its angular velocity.
4. Which of these is/are examples of conservation of linear momentum?
[A] Explosion of bomb
[B] Recoiling of a gun
[C] Fight of rockets and jet planes
[D] All of the above
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Correct Answer: D [All of the above]
Notes:Some examples of conservation of linear momentum:
- Recoiling of a gun
- Explosion of bomb
- Fight of rockets and jet planes
- A man jumping out of a boat to the shore
- A person on a frictionless surface
5. The work done by a variable force is given by:
[A] area under the force curve and the displacement axis
[B] square of the area under the force curve and the displacement axis
[C] natural log of the area under the force curve and the displacement axis
[D] twice the area under the force curve and the displacement axis
Show Answer
Correct Answer: A [area under the force curve and the displacement axis]
Notes:
The work done by a variable force is given by the area under the force curve and the displacement axis. W = Area ABCDA
6. The value of acceleration due to gravity is minimum on which of these planets?
[A] Mars
[B] Jupiter
[C] Mercury
[D] Neptune
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Correct Answer: C [Mercury]
Notes:
The value of acceleration due to gravity is minimum on planet Mercury and maximum on planet Jupiter.
7. What is the effect of increase in radius of orbit on the binding energy of a satellite?
[A] it increases
[B] it decreases
[C] It remains the same
[D] None of the above
Show Answer
Correct Answer: B [it decreases]
Notes:
The binding energy of a satellite decreases with the increase in the radius of orbit. The binding energy of a satellite is inversely proportional to the radius of orbit.
8. The distance of Neptune and Saturn from sun are nearly 1013 and 1012 meters respectively. Assuming that they move in circular orbits, what will be the ratio of their periodic times?
[A] 40
[B] 10√10
[C] 20√20
[D] 30√30
Show Answer
Correct Answer: B [10√10]
Notes:
By using Kepler’s third law, Tneptune/Tsaturn = (Rneptune/Rsaturn)3/2
9. What is the shape of meniscus when angle of contact is greater than 90°?
[A] Concave
[B] Convex
[C] Plane
[D] None of the above
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Correct Answer: B [Convex]
Notes:
When angle of contact is greater than 90°, the shape of meniscus is convex. When angle of contact is less than 90°, the shape of meniscus is concave. When angle of contact is equal to 90°, the shape of meniscus is plain.
10. What do we call the potential energy of surface molecules per unit area of the surface?
[A] Surface energy
[B] Surface Tension
[C] Reynolds number
[D] Potential constant
Show Answer
Correct Answer: A [Surface energy]
Notes:
The potential energy of surface molecules per unit area of the surface is called as surface energy. Some work is required to be done, in bringing a molecule from the interior of the liquid to the free surface, against the intermolecular force of attraction. This work which is stored as potential energy of the molecule on the surface.
