200 RAS Prelims MCQs on the basics of everyday science test the scientific method, the laws of motion, chemical bonding and the cell theory. The questions use daily-life examples, such as the recoil of a gun and the orbit of a satellite, and the explanations give the principle behind each example so that you can reason out similar questions.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
Showing 51–60 of 200 questions
RAS PrelimsScience and Technology · Basics of Everyday Science
Q51. Consider the following statements about light: I. Light travels faster in a vacuum than in glass. II. Refraction occurs when light passes from one medium to another with a different optical density. III. The angle of incidence is always less than the angle of reflection. Which of the above statement(s) is/are correct?
Explanation
Light travels at its maximum speed in a vacuum and slows down when entering denser media like glass. Refraction is the bending of light as it crosses boundaries between materials with different optical densities. Regarding reflection, the law states that the angle of incidence is always equal to the angle of reflection, not less than it, making the third statement factually incorrect.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q52. The splitting of white light into its component colors upon passing through a prism is called:
Explanation
Dispersion is the process where white light separates into its constituent colors--red, orange, yellow, green, blue, indigo, and violet--when passing through a medium like a glass prism. This happens because different wavelengths of light travel at different speeds and refract at slightly different angles. This fundamental optical phenomenon is responsible for the natural formation of rainbows in the sky after rain.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q53. The formation of a mirage in deserts is an optical illusion primarily due to:
Explanation
A mirage is an optical illusion caused by the refraction and total internal reflection of light in the atmosphere. On hot days, layers of air near the ground become much warmer and less dense than the air above. Light from the sky travels through these layers and bends upward, creating a displaced image that often looks like a pool of shimmering water.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q54. A person suffering from myopia (near-sightedness) is typically prescribed a lens of which type?
Explanation
Myopia, or near-sightedness, occurs when the eye’s lens is too curved or the eyeball is too long, causing images to focus in front of the retina rather than on it. To correct this, a concave or diverging lens is used. This lens spreads the incoming light rays outward before they reach the eye, allowing the image to focus correctly on the retinal surface.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q55. The blue color of the clear sky is mainly due to the:
Explanation
The blue appearance of the sky is a result of Rayleigh scattering. When sunlight enters the Earth’s atmosphere, it interacts with gas molecules and small particles. Shorter wavelengths of light, specifically blue and violet, are scattered in all directions more efficiently than longer wavelengths. Although violet scatters more, our eyes are more sensitive to blue, making the sky appear blue.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q56. What type of mirror is commonly used by dentists to examine teeth?
Explanation
Dentists use concave mirrors to examine teeth because they can produce a magnified, upright, and clear virtual image of an object when it is placed close to the mirror’s surface. This magnification allows the dentist to see fine details and small cavities that might be missed with the naked eye, improving diagnostic accuracy during dental procedures.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q57. Match the optical phenomena in List I with their corresponding examples in List II.
Optical Phenomenon
Example/Application
A. Total Internal Reflection
i. Rainbow formation
B. Scattering of light
ii. Twinkling of stars
C. Dispersion of light
iii. Optical fibers
D. Refraction of light
iv. Red color of sun at sunrise
Explanation
Total internal reflection is the principle behind optical fibers. Scattering of light by the atmosphere causes the sun to appear red at sunrise. Dispersion of sunlight by water droplets creates rainbows. The twinkling of stars is caused by atmospheric refraction as light passes through varying air densities. These phenomena illustrate how light interacts with different media to produce distinct visual effects.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q58. The power of a lens is measured in:
Explanation
The power of a lens is a measure of its ability to converge or diverge light rays and is mathematically defined as the reciprocal of its focal length in meters. The standard unit for measuring this power is the diopter. A lens with a short focal length has a higher power in diopters, indicating a stronger bending effect on the light passing through it.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q59. When light passes from a denser medium to a rarer medium, it bends:
Explanation
When light travels from an optically denser medium, like water, into a rarer medium, like air, its speed increases. This change in speed causes the light ray to bend away from the normal line at the boundary. If the angle of incidence exceeds a certain critical value, the light will undergo total internal reflection and remain within the denser medium entirely.
RAS PrelimsScience and Technology · Basics of Everyday Science
Q60. The speed of light in a vacuum is exactly defined as:
Explanation
The speed of light in a vacuum is a fundamental physical constant. It is defined exactly as two hundred and ninety-nine million, seven hundred and ninety-two thousand, four hundred and fifty-eight meters per second. This value is used to define the meter in the International System of Units. While often rounded for simplicity, the exact figure is fixed and unchanging in physics.
Answer key for these questions
Q
Correct answer
51
(a) I and II only
52
(d) Dispersion
53
(c) Total internal reflection
54
(b) Concave lens
55
(d) Scattering of shorter solar wavelengths by air molecules
56
(a) Concave mirror
57
(a) A-iii, B-iv, C-i, D-ii
58
(a) Diopters
59
(b) Away from the normal
60
(b) 299,792,458 m/s
Key facts from Basics of Everyday Science
Inductive reasoning draws a general conclusion from specific observations; a control variable is kept constant in an experiment; communicating the results is the last step of the scientific method.
Newton’s second law relates force, mass and acceleration; the recoil of a gun illustrates the third law.
Momentum is the product of mass and velocity; impulse is equal to the change in momentum.
A satellite in uniform circular orbit is held by the centripetal force provided by gravity.
Water (H₂O) and N₂ show covalent bonding; sodium chloride, MgO and CaF₂ are ionic.
The classical cell theory does not say that all cells have a true nucleus.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Basics of Everyday Science?
This page has 200 practice MCQs on Basics of Everyday Science (Science and Technology). Each has the correct answer, and most have an explanation.
What is the product of mass and velocity called?
Momentum. Newton’s second law says that the rate of change of momentum is equal to the force applied, and impulse is equal to the change in momentum of a body.
Which law explains the recoil of a gun?
Newton’s third law of motion. The gun pushes the bullet forward, and the bullet pushes the gun back with an equal and opposite force, which is felt as recoil.
What holds a satellite in a circular orbit?
The centripetal force provided by gravity. The Earth’s pull keeps changing the direction of the satellite’s velocity so that it moves in a circle and does not fly off in a straight line.
