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. When two mercury drops are brought into contact they form a single bigger drop to get which of the following?
[A] Minimum volume
[B] Minimum surface area
[C] Maximum size
[D] Maximum surface area
Show Answer
Correct Answer: B [Minimum surface area]
Notes:
When two drops of mercury come into contact, they will tend to merge together and form a single drop with a minimum surface area. This is because of the properties of mercury, which is a liquid metal with a high surface tension. The surface tension of a liquid is a measure of its elasticity, and it is determined by the cohesive forces between the molecules of the liquid. In the case of mercury, the high surface tension causes the molecules at the surface of the liquid to be strongly attracted to each other, which results in the formation of a relatively smooth and spherical surface. When two drops of mercury are brought together, the surface tension causes them to merge and form a single drop with the smallest possible surface area. This phenomenon is known as the “minimization of surface area” and it is a common feature of liquids with high surface tension.
2. Which among the following is measured by an Odometer?
[A] Pressure
[B] Height
[C] Distance
[D] Velocity
Show Answer
Correct Answer: C [Distance]
Notes:
An odometer is an instrument used for measuring the distance. It measures distance traveled by a vehicle such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two.
3. Which among the following orbits are more prone to harms of space debris or space Junk in comparison to others?
[A] Polar Sun Synchronous Orbit
[B] Low Earth Orbit
[C] Geosynchronous orbit
[D] Geostationary Orbit
Show Answer
Correct Answer: D [ Geostationary Orbit]
Notes:
Low Earth Orbit (LEO) is more prone to space debris or space junk. This is because space debris is more concentrated in orbits closer to Earth. Most debris is within 2,000 km (1,200 miles) of Earth’s surface.
Space debris orbits the Earth at tremendous speeds, about 15,700 miles per hour (25,265 kph) in low Earth orbit. In the event of a collision, it could cause significant damage to a satellite or spacecraft.
Experts are concerned about the amount of space debris in regions that are too high to benefit from the cleansing effects of Earth’s atmosphere. They believe that if there is too much space junk in orbit, it could result in a chain reaction where more and more objects collide and create new space junk.
4. Who among the following is credited for the Corpuscular theory of light?
[A] Isaac Newton
[B] Christiaan Hyugens
[C] Albert Einstein
[D] James Clerk Maxwell
Show Answer
Correct Answer: A [Isaac Newton]
Notes:
The Corpuscular theory of light was given by Isaac Newton. It was replaced by Huygens’ wave theory when it failed to adequately explain the diffraction, interference and polarization of light. The Huygens’ wave theory was replaced by Planck’s quantum theory and finally de-Broglie’s Dual-Theory of light replaced all previous ones.
5. Which of the following options is a representation of non-uniform motion?
[A] Equal displacements in unequal intervals of time
[B] Unequal displacements in unequal intervals of time
[C] Equal displacements in equal intervals of time
[D] Unequal displacements in equal intervals of time
Show Answer
Correct Answer: A [Equal displacements in unequal intervals of time]
Notes:
Non-uniform motion refers to the motion where the objects cover equal distances in unequal time or unequal distances in equal time. In other words, when the speed of the object is not constant, or the direction of movement of an object changes, then it is in non-uniform motion. An example of this can be any vehicle moving on a crowded city road, where it constantly changes its speed.
6. What is the product of the mass of the body and its velocity called as?
[A] Force
[B] Linear Momentum
[C] Energy
[D] Power
Show Answer
Correct Answer: B [Linear Momentum]
Notes:
Linear Momentum is the product of the mass of the body and its velocity. Linear Momentum (p) = mass(m) x velocity(v) p= mv Linear momentum is a vector quantity having the direction same as the direction of velocity of the body
7. Which of the following is NOT correct about an inelastic collision?
[A] Linear momentum is conserved
[B] Kinetic energy is conserved
[C] Total energy is conserved
[D] Some or all the forces involved may be non-conservative in nature
Show Answer
Correct Answer: B [Kinetic energy is conserved]
Notes:
Following are the basic characteristics of an inelastic collision: 1. Linear momentum is conserved 2. Kinetic energy is NOT conserved 3. Total energy is conserved 4. Some or all the forces involved may be non-conservative in nature
8. Which of the following is NOT a conservative force?
[A] Electrostatic force
[B] Magnetic force
[C] Force in an elastic spring
[D] Frictional force
Show Answer
Correct Answer: D [Frictional force]
Notes:
A conservative force is a force with the property that the work done in moving a particle between two points is independent of the taken path. Examples: Electrostatic force, Magnetic force, Force in an elastic spring Frictional force is a non-conservative force.
9. What is the coefficient of restitution for a perfectly elastic collision?
[A] 0
[B] 1
[C] -1
[D] 100
Show Answer
Correct Answer: B [1]
Notes:
For a perfectly elastic collision, the coefficient of restitution is equal to 1 as the velocity of separation after collision is equal to the velocity of approach before collision. For a perfectly inelastic collision, the coefficient of restitution is equal to 0 as the velocity of separation after collision is equal to 0. The coefficient of restitution or coefficient of resilience is the ratio of relative velocity of separation after collision and the velocity of approach before collision.
10. What is the SI unit of acceleration due to gravity?
[A] ms-2
[B] ms-3
[C] Kgms-2
[D] ms-1
Show Answer
Correct Answer: A [ms-2]
Notes:
The acceleration due to gravity is the acceleration set up in the body when it falls freely under the effect of gravity alone. The SI unit of acceleration due to gravity is ms-2