21. Consider the following statements:
- Neutrinos do not carry an electric charge but have mass.
- Neutrinos travel faster than light.
Which of the above statements is / are correct?
[A] Only 1
[B] Only 2
[C] Neither 1 nor 2
[D] Both 1 and 2
Show Answer
Correct Answer: C [Neither 1 nor 2]
Notes:
Statement 1 is correct, as neutrinos are electrically neutral particles with a very small but nonzero mass. Statement 2 is incorrect because, according to current scientific understanding, no known particle, including neutrinos, can travel faster than the speed of light in a vacuum.
22. Consider the following phenomena observed when viewing a compact disc (CD) under sunlight:
- Reflection
- Interference
- Diffraction
Which of the above phenomena are responsible for the appearance of rainbow colors on a CD surface?
[A] 1, 2 and 3
[B] Only 1 and 2
[C] Only 2 and 3
[D] Only 1 and 3
Show Answer
Correct Answer: A [1, 2 and 3]
Notes:
Rainbow colors on a CD result from a combination of reflection, interference, and diffraction of light. The microscopic grooves on the CD’s surface cause incident light to reflect at different angles, producing constructive and destructive interference patterns characteristic of diffraction gratings, resulting in the visible spectrum of colors.
23. Which among the following is/are correctly matched?
- Supergiant star – Rigel
- Giant star – Sun
- Medium size star – Betelguese
Select the correct option from the codes given below:
[A] Only 1
[B] Only 2
[C] Only 1 & 3
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
Super giant stars are huge stars. e.g Betelguese
Giant stars are large stars. e.g rigel
Medium sized stars e.g Our Sun
24. According to the International Astronomical Union (IAU), which of the following are conditions for a celestial body to be classified as a planet?
- It must be spherical.
- It must orbit a star.
- It must not share its orbital zone with other objects of similar size.
Select the correct answer using 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:
IAU defines a planet as a celestial body that (1) orbits a star, (2) is sufficiently massive for its self-gravity to assume a nearly round shape (spherical), and (3) has cleared its neighborhood around its orbit, i.e., it does not share its orbital zone with other objects of comparable size.
25. Which of the following differences between lunar regolith and terrestrial soil are correct?
- Lunar regolith doesn’t contain organic matter while terrestrial soil does.
- Lunar regolith doesn’t have water content while terrestrial soil does.
- Lunar regolith contains glassy agglutinates while terrestrial soil doesn’t.
Choose the correct answer using 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:
- The lunar regolith is very different from terrestrial soils. It doesn’t contain organic matter (worms, bacteria, decaying plant matter) that is characteristic of soil on Earth.
- Neither does it have an inherent water content.
- Metal and oxygen are common in lunar regolith.
- “Glassy agglutinates” – small mineral fragments mixed with melted glass – are abundant in lunar regolith. They are formed by a process referred to as “lunar gardening”. This is the way that the regolith changes, through bombardment of the Moon’s surface by cosmic radiation, solar wind and minuscule meteorites, also known as space weathering. Because there is no atmosphere to slow down the tiny meteorites hitting the surface, they impact at high velocity, causing melting and then quenching (rapid cooling) at the impact site.
26. Consider the following statements regarding Liquid Mirror Telescopes (LMT):
- India’s first LMT is located at the Aryabhatta Research Institute of Observational Sciences (ARIES) campus in Nainital, Uttarakhand.
- An LMT uses aluminized glass as its primary mirror.
- An LMT remains stationary and observes only the zenith as Earth rotates.
Which of the statements given above is/are correct?
[A] Only 1
[B] Only 1 and 3
[C] Only 3
[D] Only 2 and 3
Show Answer
Correct Answer: B [Only 1 and 3]
Notes:
India’s first Liquid Mirror Telescope (ILMT) is located at the ARIES campus. Unlike conventional telescopes, LMTs use a rotating layer of liquid mercury as the reflective surface, not aluminized glass. They remain stationary, focusing vertically at the zenith, observing as the Earth rotates. Thus, statements 1 and 3 are correct; statement 2 is not.
27. Consider the following statements:
- Rotation is the movement of the earth around the sun in its orbit.
- The period of rotation is known as the earthday.
Which of the above is / are correct?
[A] Only 1
[B] Only 2
[C] Both 1 and 2
[D] None of the above
Show Answer
Correct Answer: B [Only 2]
Notes:
Rotation is the movement of the earth on its axis. The earth takes about 24 hours to complete one rotation around its axis. The period of rotation is known as the earthday. This is the daily motion of the earth.
28. Consider the following statements about motion.
- Motion is observed when its position changes with time.
- If an object moves very slowly then its movement can be observed easily.
- Rectilinear motion takes place in a fixed direction.
Which of the above is / are correct?
[A] Only 1 and 3
[B] Only 2 and 3
[C] Only 1 and 2
[D] All of the above
Show Answer
Correct Answer: A [Only 1 and 3]
Notes:
The movement of an object is called motion and an object is said to be in motion when its position changes with time. if an object moves very fast then its movement can be observed easily but if an object moves very slowly, then it becomes difficult to observe its movement immediately. Motion in a straight line is called rectilinear motion. Example: the movement of a bullet fired from a gun is an example of rectilinear motion. Rectilinear motion takes place in a fixed direction. The motion which repeats itself after regular intervals of time is called periodic motion.
29. Which of the following will produce diffuse reflection of light?
- Plane mirror
- Piece of paper
- Still water in lake
- Leather bag
Select the correct answer from the codes given below:
[A] Only 1 and 2
[B] Only 2 and 3
[C] Only 1 and 4
[D] Only 2 and 4
Show Answer
Correct Answer: D [Only 2 and 4]
Notes:
Due to rough surfaces, most of the objects reflect light in all directions. This is called a regular reflection or diffuse reflection. For example, a white piece of paper has a rough surface so it reflects lights falling on it in all directions. Similar is the case with the leather bag.
30. Which of the following are requirements for producing fire?
- Fuel
- Air
- Heat
Select the correct answer from the codes given below:
[A] Only 1 and 2
[B] Only 1 and 3
[C] Only 2 and 3
[D] All of the above
Show Answer
Correct Answer: D [All of the above ]
Notes:
The essential requirements for producing fire are: fuel, air (to supply oxygen) and heat (to raise the temperature of the fuel beyond the ignition temperature).
