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. What is the focal length of a concave lense with number -5D?
[A] 5 cm
[B] 10 cm
[C] 15 cm
[D] 20 cm
Show Answer
Correct Answer: D [20 cm]
Notes:
A concave lens is a type of lens that has a thinner center than edges, and it is sometimes called a diverging lens because it spreads out light rays that are parallel to its axis. The focal length of a lens is a measure of its ability to focus light, and it is defined as the distance from the lens to the point where the light rays converge. In the case of a concave lens with a power of -5D, the focal length would be equal to 1/5 of a meter, or 20 centimeters.
2. A pendulum is taken to Moon, what will happen to its time period?
[A] Increases
[B] Decreases
[C] Remains constant
[D] Either increase or decrease
Show Answer
Correct Answer: A [Increases]
Notes:
When the simple pendulum is taken to the moon, value of gravitational constant g will decrease and thus, its time period will increase.
3. Which among the following is true about latent heat ?
[A] It causes change in temperature as well as change in state or phase
[B] It causes change in temperature only
[C] It causes change in state or phase but not in temperature
[D] It causes change in Pressure
Show Answer
Correct Answer: C [It causes change in state or phase but not in temperature]
Notes:
The latent heat Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. It causes change in state or phase but not in temperature.
4. Edwin Howard Armstrong was an inventor of which of the following technologies?
[A] Television
[B] Compact Discs
[C] FM Radio
[D] Broadband
Show Answer
Correct Answer: C [FM Radio]
Notes:
Edwin Howard Armstrong was an American electrical engineer who developed FM radio and the superheterodyne receiver system. Edwin Howard Armstrong is the “father of FM radio” and was born in 1890.
5. A long Rail (approximately 700 meters) made up of steel is struck to produce a sound. The person standing on the other end of the rail would hear in which among the following pattern?
[A] He listens the sound waves once propagated via steel
[B] He listens the sound waves once propagated via air
[C] He listens the sound waves twice, first propagated via steel and second propagated via air
[D] He listens the sound waves twice, first propagated via air and second propagated via steel
Show Answer
Correct Answer: C [He listens the sound waves twice, first propagated via steel and second propagated via air]
Notes:
The correct answer is that the person hears the sound waves twice: first via steel and then via air. Sound travels faster in solids than in gases. in steel, it travels at about 5,960 m/s, while in air, it travels at approximately 343 m/s. Given the long distance of 700 meters, the sound will reach the person through the steel rail first, followed by the sound traveling through the air. This phenomenon illustrates the differences in sound propagation speeds in different media.
6. 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.
7. Which among the following Radio frequencies are used around the world in air navigational system?
[A] Very Low Frequency (VLF)
[B] Very High Frequency (VHF)
[C] Tetrahertz Radiation (THF)
[D] Ultra High Frequency (UHF)
Show Answer
Correct Answer: B [ Very High Frequency (VHF)]
Notes:
VHF (Very High Frequency) omnidirectional radio range (VOR), is a short-range radio navigation system for aircraft, enabling aircraft to determine their position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons, with a receiver unit. Uses radio frequencies in the very high frequency (VHF) band from 108 to 117.95 MHz. VOR is the standard air navigational system in the world, used by both commercial and general aviation.
8. Linear momentum can be described in which of the following units?
[A] kgm2/s2
[B] kg/ms2
[C] kg/ms
[D] kgm/s
Show Answer
Correct Answer: D [ kgm/s ]
Notes:
The SI unit of Linear Momentum is kg m/s Linear Momentum = Mass(kg) x Velocity (m/s) Linear Momentum is the quantity of motion of a moving body. Dimensional Formula of Linear Momentum is [M1 L1 T-1]
9. The branch of mechanics which deals with the study of motion of material objects without taking into account the factors which cause motion is called as:
[A] Statics
[B] Kinematics
[C] Dynamics
[D] None of the above
Show Answer
Correct Answer: B [Kinematics]
Notes:
The branch of mechanics which deals with the study of motion of material objects without taking into account the factors which cause motion is called as Kinematics. The branch of mechanics which deals with the study of motion of material objects taking into account the factors which cause motion is called as Dynamics. The branch of mechanics which deals with the study of material objects at rest is called as Statics.
10. The inablity of a body to change its state of rest or motion is known as:
[A] Force
[B] Momentum
[C] Displacement
[D] Inertia
Show Answer
Correct Answer: D [Inertia]
Notes:
Inertia is the property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force. There are three types of Inertia: 1. Inertia of rest 2. Inertia of motion 3. Inertia of direction