Question 1

Which of the following is the SI unit of electric current?

Accepted Answer

The SI unit of electric current is the Ampere (A), named after French physicist André-Marie Ampère. It is defined as the flow of one coulomb of charge per second through a conductor.

Question 2

Which of the following is an example of a scalar quantity?

Accepted Answer

A scalar quantity is a physical quantity that has only magnitude (size) and no direction. Examples include speed, distance, mass, temperature, and time. In contrast, vector quantities have both magnitude and direction, such as velocity, displacement, and force.

Question 3

What is the SI unit of force?

Accepted Answer

The Newton (N) is the SI unit of force, named after Sir Isaac Newton. One Newton is defined as the force required to accelerate a mass of one kilogram at a rate of one meter per second squared (1 N = 1 kg·m/s²).

Question 4

Which physical quantity is measured in Hertz (Hz)?

Accepted Answer

Hertz (Hz) is the SI unit of frequency, named after physicist Heinrich Hertz. It measures the number of cycles or oscillations per second. One Hertz equals one cycle per second.

Question 5

Which scientist formulated the law of universal gravitation?

Accepted Answer

Sir Isaac Newton formulated the law of universal gravitation in the late 17th century. This law states that every mass attracts every other mass with a force proportional to the product of their masses and inversely proportional to the square of the distance between them (F = G m₁m₂/r²).

Question 6

What is the SI unit of temperature?

Accepted Answer

The Kelvin (K) is the SI unit of absolute temperature, named after physicist William Thomson, Lord Kelvin. It is an absolute temperature scale where 0 K represents absolute zero, the lowest possible temperature.

Question 7

Which of the following is the SI unit of energy?

Accepted Answer

The Joule (J) is the SI unit of energy and work. One Joule is defined as the amount of energy transferred when a force of one Newton acts over a distance of one meter (1 J = 1 N·m). It is named after English physicist James Prescott Joule.

Question 8

Which physicist discovered the law of universal gravitation?

Accepted Answer

Sir Isaac Newton discovered the law of universal gravitation in the late 17th century. This law states that every mass attracts every other mass with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.

Question 9

What is the SI unit of energy?

Accepted Answer

The Joule (J) is the SI unit of energy, named after English physicist James Prescott Joule. One Joule is defined as the energy transferred when a force of one Newton is applied over a distance of one metre (1 J = 1 N⋅m).

Question 10

What is the primary reason that objects appear to have weight when standing on Earth's surface?

Accepted Answer

Objects appear to have weight because Earth's gravitational field exerts a downward force on them. Weight is the force exerted by gravity on an object's mass (W = mg, where g ≈ 9.8 m/s² on Earth's surface). This gravitational pull creates the sensation of weight.

Question 11

What is the SI unit of pressure?

Accepted Answer

The SI unit of pressure is the Pascal (Pa), named after French mathematician and physicist Blaise Pascal. One Pascal is defined as one Newton of force applied over one square meter of area (1 Pa = 1 N/m²).

Question 12

Which of the following correctly describes the relationship between velocity and acceleration?

Accepted Answer

Acceleration is the rate of change of velocity with respect to time. It is a vector quantity that can be positive (speeding up), negative (slowing down), or zero (constant velocity). Acceleration = Δv/Δt.

Question 13

Which of the following phenomena explains why a wet surface dries faster on a windy day than on a calm day?

Accepted Answer

Evaporation is the process by which liquid water converts to water vapour. Wind increases the rate of evaporation by removing the layer of saturated air above the water surface, allowing more water molecules to escape into the atmosphere.

Question 14

What is the phenomenon by which light bends when passing from one medium to another?

Accepted Answer

Refraction is the bending of light when it passes from one transparent medium to another with a different optical density. This occurs because light travels at different speeds in different media.

Question 15

Which phenomenon is responsible for the formation of a rainbow after rainfall?

Accepted Answer

A rainbow is formed due to the dispersion, refraction, and total internal reflection of sunlight by water droplets suspended in the atmosphere. White sunlight is split into its constituent seven colours (VIBGYOR) as it passes through the water droplets.

Question 16

Which of the following best explains why a mirror produces a clear reflection while frosted glass does not?

Accepted Answer

A mirror has a smooth, polished surface that reflects light rays in a parallel, organized manner (specular reflection), producing a clear image. Frosted glass has a rough, uneven surface that scatters light rays in random directions (diffuse reflection), preventing a clear image from forming.

Question 17

Which of the following statements about friction is correct?

Accepted Answer

Friction is a force that opposes relative motion between two surfaces in contact. It acts parallel to the surfaces and depends on the normal force and the coefficient of friction between the materials.

Question 18

A person uses a convex lens of focal length 20 cm to view a small object placed 15 cm from the lens. What type of image is formed, and where?

Accepted Answer

Using the lens formula: 1/f = 1/u + 1/v, where f = 20 cm, u = 15 cm. Solving: 1/20 = 1/15 + 1/v → 1/v = 1/20 - 1/15 = -1/60 → v = -60 cm. A negative image distance indicates a virtual image on the same side as the object.

Question 19

Which phenomenon explains why the sky appears blue during the day but red/orange during sunrise and sunset?

Accepted Answer

The blue colour of the sky is due to Rayleigh scattering, where shorter wavelengths (blue) are scattered more by atmospheric particles. During sunrise/sunset, sunlight travels a longer path through the atmosphere, causing blue light to scatter away and leaving longer wavelengths (red/orange) dominant. Rayleigh scattering intensity is inversely proportional to the fourth power of wavelength (∝ 1/λ⁴).

Question 20

In physics, the SI unit of pressure is the Pascal (Pa). How many Pascals are equivalent to 1 atmosphere of pressure at sea level?

Accepted Answer

1 atmosphere (atm) = 101,325 Pa ≈ 101.325 kPa. This is the standard atmospheric pressure at sea level, a fundamental reference point in physics and engineering.

SSC CHSL Physics — Everyday Concepts

Physics — Everyday Concepts— Rules & Concept

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Physics — Everyday Concepts — Practice Questions

60-Second Revision — Physics — Everyday Concepts