General Science - Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examinations.
1. Which among the following temperature scale is based upon absolute zero?
[A] Celsius
[B] Fahrenheit
[C] Kelvin
[D] Rankine
Show Answer
Correct Answer: C [Kelvin]
Notes:
Kelvin is the base unit of temperature (SI unit), having the unit symbol K. The Kelvin temperature scale has an absolute zero (0°K) below which temperatures do not exist. It is the lowest possible temperature. At this temperature there is no motion and no heat. It is equivalent to 0°K, or -273.15° C, or at -460° F.
2. Consider the following statements:
- International Space Station is stationary, when seen from Earth
- An astronaut in International Space Station feels complete weightlessness
- International Space Station is always in a state of Free fall
Which among the above statements is/ are correct?
[A] Only 1 is correct
[B] Only 3 is correct
[C] 2 & 3 are correct
[D] 1 , 2 & 3 are correct
Show Answer
Correct Answer: B [Only 3 is correct]
Notes:
The International Space Station (ISS) is not stationary. It is moving around the Earth. The ISS and the astronauts, the ISS itself are not floating, they are actually falling as they are in motion. But their sufficient velocity allows them to stay in the Earth orbit. Though the astronauts feel weightless inside the ISS it is not complete weightlessness. They experience microgravity.
3. The wavelengths for the light of red and blue colours are distinctly different. In this context, consider the following statements:
1. In vacuum, both red and blue colours have same speed
2. In glass, the speed of red colour is more than blue colour
Which among the above statements is / are correct?
[A] Only 1 is correct
[B] Only 2 is correct
[C] Both 1 & 2 are correct
[D] Neither 1 nor 2 is correct
Show Answer
Correct Answer: C [ Both 1 & 2 are correct]
Notes:
Both 1 & 2 are correct statements
4. Consider the following statements:
1. Infra-red radiations produce heating effect, but not the visible radiation.
2. Infra-red radiations do not get scattered as easily as compared to visible light
Which among the above statements is / are correct?
[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: C [ Both 1 & 2]
Notes:
Both are correct statements
5. Which of the following is / are correct statements with respect to the image formed in a plane mirror?
- Image is always virtual
- The distance of image from the mirror is same as the distance between object and mirror
- Image is laterally inverted
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: D [ 1, 2 & 3]
Notes:Chief characteristics of an image formed in plane mirror are:
- Image is erect and of equal size.
- Image is virtual, it means the image cannot be taken on screen.
- The distance of image from the mirror is same as the distance between object and mirror.
- Image is laterally inverted. It means right hand side of the object appears as left hand side of the image and vice versa.
6. Which of the following is / are correct statements about the Millimeter waves, sometimes seen in news?
- These are among the highest radio frequency band
- They have higher wavelength than Microwaves
- They are most notably used in security appliances
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: C [ Only 1 & 3]
Notes:
Millimeter Waves correspond to the EHF Band which runs the range of frequencies from 30 to 300 gigahertz, above which electromagnetic radiation is considered to be low (or far) infrared light, also referred to as terahertz radiation. This band has a wavelength of ten to one millimetre. The Microwaves have wavelength of from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz) and 300 GHz. Thus statement 2 is incorrect.
7. A Pendulum Clock, whose pendulum is made up of a steel rod, will become slow if __:
1. Temperature rises
2. Taken to moon
3. Taken from equator to pole
Choose the correct option from the codes given below:
[A] Only 1
[B] Only 1 & 2
[C] Only 2 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: B [ Only 1 & 2]
Notes:
The length of the pendulum increases if temperature increases and the time period T increases and a pendulum takes more time to complete one oscillation. That is why it becomes slow. As the moon’s gravity of about 1/6 of Earth’s gravity, and period of a pendulum increases with a decrease in gravity so it will take more time to complete one oscillation. When a pendulum is taken from the equator to the pole, gravity increases, Time period decreases and it will start oscillating faster.
8. Consider the following:
1. Formation of a rainbow
2. Dispersion of light,
3. A coin appears raised when placed in a trough filled with water
Which among the above refraction?
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: D [ 1, 2 & 3]
Notes:
Refraction is a phenomenon of light, sound wave, water wave by which the direction of a wave changed while passing from one medium to another. Some of the examples of refraction are Mirage, appearing of raised coin in a trough filled with water, bent pencil in glass of water, rainbow, dispersion of light sunset, etc.
9. Which among the following is / are correct statements?
1. Friction converts Kinetic energy to radiation energy
2. A collision of two bodies can be said to be perfectly inelastic if no energy is exchanged between them
Select the correct option from the codes given below:
[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: A [ Only 1]
Notes:
The collision of two bodies can be said to be inelastic when permanent deformations occur in them.
10. Direct Current produces a magnetic field similar to a permanent magnet. This magnetic field:
[A] is unidirectional and has a steady magnitude
[B] is unidirectional but its magnitude varies in regular pattern
[C] has steady magnitude but changes direction in regular pattern
[D] changes direction and magnitude in regular pattern
Show Answer
Correct Answer: A [ is unidirectional and has a steady magnitude]
Notes:
A coil or conductor carrying direct current (DC) produces a magnetic field similar to a permanent magnet. The current carried by this conductor is unidirectional and steady i.e. it does not change direction or vary in magnitude with respect to time. Hence, the effect is that of a permanent magnet which simply attracts objects near the coil. However, in case of Alternating current, the magnetic field changes direction, i.e. it becomes negative for the second half of the frequency cycle (50 cycles per second in India). Further, its magnitude varies sinusoidally (curve having a sinewave form) thereby becoming zero at the end of a cycle.
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