Very Short Answers - Light, Science, Class 8 | Science Class 8 PDF Download

 Q1: What makes things visible?

Ans: Light.

Light

Q2: Can you see an object in the dark?

Ans: No.

DarkQ3: What is a mirror?

Ans: A smooth and shiny surface is called a mirror.

MirrorQ4: What kind of image is formed by a plane mirror?

Ans: Virtual and erect image.

Q5: Where is the image formed by a plane mirror?

Ans: Behind the mirror. 

Q6: Where does the image form in our eyes?

Ans: At Retina. 

RetinaQ7: Where is no image formed?

Ans: Blind spot.

Q8: For what time the image stays on the retina?

Ans: About 1/16th of a second.

Q9:Which bird is called night bird?

Ans: Owl is called night bird. 

Owl Q10: Which surface shows regular reflection?

Ans: Smooth or regular surface.

 Regular SurfaceQ11: Which surface shows diffused reflection?

Ans: Rough or irregular surface.

Irregular SurfaceQ12: What is the size of the image formed in a plane mirror?

Ans: Same size of the object.

Q13: How many mirrors are used in Kaleidoscope?

Ans: Three mirrors.

KaleidoscopeQ14: How many colours are there in the spectrum of light?

Ans: Seven colours.

Q15: How many colours are there in white light?

Ans: Seven colours.

Q16: What is the shape of the human eye?

Ans: Spherical shape.

EyeQ17: What is the front transparent part of the eye called?

Ans: Cornea.

CorneaQ18: What is the small opening in the iris called?

Ans: Pupil.

PupilQ19: Which part of the eye is controlled by the iris?

Ans: Pupil.

Q20: What is the coloured part of the eye called?

Ans: Iris.

Q21: What is the function of the iris?

Ans: Iris controls the amount of light entering the eye through the pupil.

Q22: Which part of the body sends the sensation felt to the brain?

Ans: Nerve cells.

Nerve cellsQ23: How many kinds of nerve cells are there in the retina?

Ans: Two (cones and rods).

Two (cones and rods).Q24: Which cells of the retina are sensitive to bright light and colour?

Ans: Cones.

Q25: Which cells of the retina are sensitive to dim light?

Ans: Rods.

Q26: What is the distinct vision of the normal eye?

Ans: 25 cm.

Q27:  Who invented the system of reading for blind men?

Ans: Braille.

BrailleQ28: Which element is used at the back of plane mirror?

Ans: Silver

Q29: The distance between the object and its image formed by a plane mirror appears to be 18 cm. What is the distance between mirror and the object?

Ans: 9 cm

Q30: A ray of light is incident on a mirror at an angle of 40°. What is the angle of reflect?

Ans: 40°

Q31: Name a device which works on the principle of multiple reflection.

Ans: Periscope

PeriscopeQ32: Give an example of night bird.

Ans: Owl

Q33:  What do we call the image that cannot be obtained on a screen?

Ans: Virtual

Q34: Name the liquid found between the cornea and lens.

Ans: Aqueous humour

Aqueous humourQ35: Name the liquid found between the lens and the retina.

Ans: Vitreous humour

Vitreous Humour