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 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.
2. Which among the following sentence is correct reason behind the blue color of ocean water?
[A] Water molecules absorb all other colors except blue
[B] Impurities in Sea water reflect the blue light
[C] Water molecules scatter the blue light
[D] None of the above
Show Answer
Correct Answer: C [Water molecules scatter the blue light]
Notes:
Water molecules scatter the blue light by absorbing the light waves and then rapidly re-emitting the light waves in different directions. That is why there are mostly blue wavelengths that are reflected back to our eyes.
3. 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.
4. Newton-meters per second is represented as follows?
[A] Ohm
[B] Volt
[C] Watt
[D] Calorie
Show Answer
Correct Answer: C [Watt]
Notes:
one watt is the rate at which work is done when an object is moved at a speed of one meter per second against a force of one Newton.
5. Which among the following provides potential energy to an object?
[A] Its momentum
[B] It’s position
[C] It’s acceleration
[D] It’s shape
Show Answer
Correct Answer: B [ It’s position]
Notes:
The potential energy is defined as the energy that is stored in an object due to its position. Various types of potential energy include the gravitational potential energy (depends on its mass and its distance from the center of other object’s mass), the elastic potential energy, the electric potential energy.
6. On heating a pure silicon circular disc with a circular hole at the centre, the diameter of the hole:
[A] will expand
[B] will contract
[C] will remain constant
[D] may expand or contract
Show Answer
Correct Answer: B [ will contract]
Notes:
Pure silicon has a negative coefficient of thermal expansion for temperatures and hence it shows contraction effect.
7. Which among the following is the correct sequence of the terms used for various phases of the rocky object from space entering earth’s atmosphere and reaching on earth?
[A] Meteoroid – Meteor – Meteorite
[B] Meteorite – Meteoroid – Meteor
[C] Meteor – Meteorite – Meteoroid
[D] Meteoroid – Meteorite – Meteor
Show Answer
Correct Answer: A [ Meteoroid – Meteor – Meteorite]
Notes:
A meteoroid is a small rocky or metallic body travelling through space. When such an object enters the Earth’s atmosphere, it heats up from atmospheric friction and produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor, or colloquially a “shooting star” or “falling star”. If a meteoroid, comet or asteroid or a piece thereof withstands ablation from its atmospheric entry and impacts with the ground, then it is called a meteorite. (Wikipedia)
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 relationship between Kinetic and limiting friction?
[A] Kinetic friction is slightly greater than limiting friction
[B] Kinetic friction is slightly less than limiting friction
[C] Kinetic friction is equal to limiting friction
[D] No relationship
Show Answer
Correct Answer: B [Kinetic friction is slightly less than limiting friction]
Notes:
The Kinetic friction is always slightly less than the limiting friction. This is because once the motion has started, the inertia of has been overcome and irregularities of one surface have little or no time to get locked into the irregularities of the other surface.
10. 1 kilogram force produces how much acceleration in a body of mass 1 kg?
[A] 1 ms-2
[B] 0
[C] 9.8 ms-2
[D] -1 ms-2
Show Answer
Correct Answer: C [9.8 ms-2]
Notes:
1 Kilogram force or 1 Kilogram weight is that much force which produces an acceleration of 9.8 ms-2 in a body of mass 1 kg. Also, 1 kg wt. or 1 kg f = 9.8 N
