In a class 10th physics curriculum, the topic of “Light” is typically covered as part of the optics section. Here is a short note on the basic concepts related to light:
MCQs on light class 10th practice now
Introduction to Light:
- Light is a form of electromagnetic radiation that is visible to the human eye. It is a type of energy that travels in the form of waves.
Properties of Light:
- Rectilinear Propagation: Light travels in straight lines. When it encounters an obstacle, it casts a shadow that has a well-defined outline.
- Reflection: When light bounces off a surface, it is called reflection. The angle of incidence is equal to the angle of reflection, as per the law of reflection.
- Refraction: Refraction is the bending of light when it passes from one medium to another with a different optical density. This bending is responsible for phenomena like the bending of a straw in a glass of water.
- Dispersion: When white light passes through a prism, it separates into its constituent colors, forming a spectrum. This phenomenon is called dispersion.
- Luminous and Non-luminous Objects: Objects that emit their own light are called luminous objects (e.g., the Sun, a light bulb). Non-luminous objects do not emit their own light but can reflect light from other sources (e.g., the Moon, a book).
Reflection of Light:
- The reflection of light allows us to see objects. A mirror is a common example of a reflective surface.
- The image formed in a plane mirror is virtual, erect, and of the same size as the object.
Refraction of Light:
- Refraction occurs when light passes from one medium (like air) into another (like water or glass).
- The change in speed and direction of light leads to the bending of light rays.
- Refraction is responsible for the apparent bending of a pencil when it is partially submerged in water.
Dispersion of Light:
- White light is a mixture of all colors of the visible spectrum.
- When white light passes through a prism, it is dispersed into its constituent colors, creating a spectrum that ranges from red to violet.
Applications of Light:
- Light has numerous practical applications, including in optics, photography, and the functioning of optical devices like microscopes, telescopes, and cameras.
- Fiber optics, which use light to transmit data, are widely used in telecommunications.
Understanding the fundamentals of light is essential not only for academic purposes but also for comprehending the workings of various optical instruments and their applications in everyday life.
MCQs on light class 10th
1. What is the speed of light in a vacuum?
a) 300,000 meters per second
b) 150,000 meters per second
c) 500,000 meters per second
d) 1,000,000 meters per second
2. Which colour of light has the longest wavelength?
a) Red
b) Blue
c) Green
d) Yellow
3. In which medium does light travel the fastest?
a) Water
b) Air
c) Glass
d) Vacuum
4. What type of mirror is used in a rearview car mirror?
a) Concave
b) Convex
c) Plane
d) Spherical
5. Which law of reflection states that the angle of incidence is equal to the angle of reflection?
a) Newton’s First Law of Reflection
b) Law of Refraction
c) Snell’s Law
d) Law of Reflection
6. What is the colour of an object that appears black in white light?
a) It absorbs all colors
b) It reflects all colors
c) It absorbs red light
d) It absorbs green light
7. Which lens can converge parallel rays of light?
a) Concave lens
b) Convex lens
c) Plano-concave lens
d) Plano-convex lens
8. What is the unit of measurement for the intensity of light?
a) Watts
b) Lumens
c) Decibels
d) Hertz
9. Which phenomenon causes a rainbow to form in the sky?
a) Reflection
b) Dispersion
c) Refraction
d) Diffraction
10. Which type of mirror is commonly used by dentists to see a larger image of the patient’s teeth?
a) Concave mirror
b) Convex mirror
c) Plane mirror
d) Spherical mirror
11. When light passes from air into water, it generally…
a) Speeds up
b) Slows down
c) Changes direction
d) Disappears
12. What is the process of bending of light as it passes from one medium to another called?
a) Reflection
b) Dispersion
c) Refraction
d) Absorption
13. Which color of light has the shortest wavelength?
a) Red
b) Blue
c) Green
d) Yellow
14. What does a convex lens do to incoming light rays?
a) Diverges them
b) Absorbs them
c) Focuses them
d) Scatters them
15. What type of lens is used in a magnifying glass?
a) Concave
b) Convex
c) Plano-concave
d) Plano-convex
16. Which law states that the angle of incidence, the angle of refraction, and the speed of light are related when light passes through different mediums?
a) Newton’s First Law of Reflection
b) Law of Refraction
c) Snell’s Law
d) Law of Reflection
17. What happens to the speed of light when it travels from a denser medium to a rarer medium?
a) It increases
b) It decreases
c) It remains the same
d) It depends on the angle
18. Which type of lens is used to correct nearsightedness (myopia)?
a) Concave lens
b) Convex lens
c) Plano-concave lens
d) Plano-convex lens
19. When light is refracted, the change in direction is due to a change in…
a) Speed
b) Frequency
c) Wavelength
d) Intensity
20. Which part of the eye is responsible for focusing incoming light onto the retina?
a) Cornea
b) Retina
c) Lens
d) Iris
21. What is the phenomenon that occurs when light waves interact with small obstacles and change direction?
a) Reflection
b) Refraction
c) Diffraction
d) Dispersion
22. What type of mirror is commonly used in makeup mirrors?
a) Concave mirror
b) Convex mirror
c) Plane mirror
d) Spherical mirror
23. Which of the following colors of light is not part of the visible spectrum?
a) Violet
b) Red
c) Ultraviolet
d) Blue
24. What is the angle of incidence when light is incident at 90 degrees to the surface?
a) 0 degrees
b) 30 degrees
c) 45 degrees
d) 60 degrees
25. When white light passes through a prism, it separates into its constituent colors. What is this phenomenon called?
a) Reflection
b) Refraction
c) Dispersion
d) Diffraction
26. What is the name for the phenomenon when light bounces off a surface in many different directions?
a) Refraction
b) Diffraction
c) Dispersion
d) Scattering
27. What is the focal point of a concave mirror for parallel rays of light?
a) It is on the mirror’s surface
b) It is behind the mirror
c) It is in front of the mirror
d) It does not have a focal point
28. Which type of lens is used in a camera to focus light onto the film or sensor?
a) Concave lens
b) Convex lens
c) Plano-concave lens
d) Plano-convex lens
29. When light travels from a rarer medium to a denser medium, it generally…
a) Speeds up
b) Slows down
c) Changes direction
d) Disappears
30. Which part of the eye controls the size of the pupil and the amount of light entering the eye?
a) Cornea
b) Retina
c) Lens
d) Iris
31. What is the phenomenon that occurs when light waves bounce back after hitting a surface?
a) Reflection
b) Refraction
c) Diffraction
d) Dispersion
32. What is the unit of measurement for the wavelength of light?
a) Meters
b) Hertz
c) Nanometers
d) Watts
33. Which type of mirror is commonly used in makeup mirrors?
a) Concave mirror
b) Convex mirror
c) Plane mirror
d) Spherical mirror
34. What is the angle of incidence when light is incident at 90 degrees to the surface?
a) 0 degrees
b) 30 degrees
c) 45 degrees
d) 60 degrees
MCQs on light class 10th
Light is a form of electromagnetic radiation that is visible to the human eye. It consists of photons and travels in the form of waves. It is the reason we can see objects and our surroundings
How does reflection work?
Reflection is the bouncing back of light when it encounters a surface. According to the law of reflection, the angle of incidence (the angle at which light strikes a surface) is equal to the angle of reflection (the angle at which light bounces off the surface).
What is refraction, and why does it occur?
Refraction is the bending of light when it passes from one medium into another of different optical density. This bending occurs due to a change in the speed of light as it moves from one medium to another. It is responsible for phenomena like the apparent bending of a straw in a glass of water.
Why does a prism create a spectrum of colors from white light?
A prism separates white light into its constituent colors because different colors of light are bent by different amounts as they pass through the prism. This dispersion of colors is due to the varying wavelengths of different colors in the visible spectrum.
What are the differences between luminous and non-luminous objects?
Luminous objects are those that emit their own light, such as the Sun or a light bulb. Non-luminous objects do not emit light but can reflect or scatter light from other sources, making them visible. Examples of non-luminous objects include the Moon, planets, and everyday objects like books and furniture.