Extra 30 short questions and answers for the "Light" chapter:13 of Class 8 CBSE Science:-
Q: What is reflection of light?
A:
Reflection is the bouncing back of light from a surface. The angle of incidence is equal to the angle of reflection.
Q: What is a plane mirror?
A:
A plane mirror is a flat, smooth reflecting surface. It forms a virtual and erect image of the same size as the object.
Q: What is a convex mirror?
A:
A convex mirror is a curved mirror with an outward reflecting surface. It forms a diminished and virtual image.
Q: What is a concave mirror?
A:
A concave mirror is a curved mirror with an inward reflecting surface. It can form both real and virtual images.
Q: What is refraction of light?
A:
Refraction is the bending of light as it passes from one medium to another. It occurs due to the change in the speed of light.
Q: What is dispersion of light?
A:
Dispersion is the splitting of white light into its component
colours
. It occurs when light passes through a prism.
Q: What are the
colours
of the visible spectrum?
A:
The
colours
of the visible spectrum are Violet, Indigo, Blue, Green, Yellow, Orange, and Red (VIBGYOR).
Q: What is the iris of the human eye?
A:
The iris is the
coloured
part of the eye. It controls the size of the pupil.
Q: What is the pupil of the human eye?
A:
The pupil is the small opening in the
centre
of the iris. It allows light to enter the eye.
Q: What is the cornea of the human eye?
A:
The cornea is the transparent front part of the eye. It helps to focus light onto the retina.
Q: What is the lens of the human eye?
A:
The lens is a convex lens that focuses light onto the retina. It adjusts its shape to focus on objects at different distances.
Q: What is the retina of the human eye?
A:
The retina is the light-sensitive layer at the back of the eye. It contains rods and cones.
Q: What are rods in the retina?
A:
Rods are cells in the retina sensitive to dim light. They help us see in low light conditions.
Q: What are cones in the retina?
A:
Cones are cells in the retina sensitive to bright light and
color
. They help us see
colours
.
Q: What is the optic nerve?
A:
The optic nerve transmits visual information from the retina to the brain.
Q: What is a luminous object?
A:
A luminous object is an object that produces its own light, like the sun or a light bulb.
Q: What is a non-luminous object?
A:
A non-luminous object is an object that reflects light, like the moon or a table.
Q: What is a ray of light?
A:
A ray of light is a straight line representing the path of light.
Q: What is a beam of light?
A:
A beam of light is a collection of light rays.
Q: What is the angle of incidence?
A:
The angle of incidence is the angle between the incident ray and the normal to the reflecting surface.
Q: What is the angle of reflection?
A:
The angle of reflection is the angle between the reflected ray and the normal to the reflecting surface.
Q: Why is a convex mirror used as a rear-view mirror?
A:
It provides a wider field of view and forms erect images.
Q: Why is a concave mirror used by dentists?
A:
It forms an enlarged image of teeth, making it easier to examine them.
Q: What happens when white light passes through a prism?
A:
It splits into its component
colours
, forming a spectrum.
Q: What is the function of the pupil?
A:
It controls the amount of light entering the eye.
Q: What is the function of the lens?
A:
It focuses light onto the retina.
Q: What is the function of the cornea?
A:
It helps in the refraction of light and protects the eye.
Q: What is the difference between real and virtual images?
A:
A real image can be formed on a screen, while a virtual image cannot.
Q: What are the primary
colours
of light?
A:
The primary
colours
of light are red, green, and blue.
Q: What is the relationship between the angle of incidence and the angle of reflection?
A:
The angle of incidence is equal to the angle of reflection.
