41) What type of mirrors are used as shaving mirrors?
Ans) Parabolic mirrors
42) Why red is used as an emergency or danger signal?
Ans) As its wavelength is the longest
43) Rainbow is seen after rain because of hanging molecules of water which acts as?
Ans) Prisms
44) Red light is used in signals because it has?
Ans) Low refraction in the medium
45) A periscope works on the principle of?
Ans) Total internal reflection
46) A rear-view mirror for driving is?
Ans) Convex
47) What is the lens made up of?
Ans) Flint glass
48) On which principle does optical fiber works?
Ans) Total internal reflection
49) Mirage is an example of?
Ans) Refraction and total internal reflection of light
50) Forged document are detected by? Important Science Objective Questions Ans) Ultraviolet rays
51) A Concave lens always forms an image which is?
Ans) Virtual and erect
52) A person wears a spectacle with concave lenses. it means that normally the image of a distinct object is focused in his eyes?
Ans) In front of the retina
53) A microscope used in pathological laboratories forms?
Ans) Magnified, virtual and inverted image
54) The sparkling of a diamond is due to?
Ans) Total internal reflection
55) Short-sight in the human can be corrected by using?
Ans) Concave lens
56) Which color of light shows maximum deviation when passed through a prism? Ans) Violet
57) Which type of mirror is used in the headlight of vehicles?
Ans) Concave mirror
58) The reason for a swimming pool to appear less deep then the actual depth is?
Ans) Refraction
59) X-rays region lies between?
Ans) Gamma-rays and ultraviolet region
60) A star appears twinkling in the sky because of?
Ans) Refraction of light by the atmosphere
