61. Which one, is not a rough, surface called ____________________?
(a) Wall
(b) Paper
(c) Cloth
d) Mirror
62. Mirrors used, in car head lights, and search light, are?
(a)Convex
(b) Plane
(c) Concave
(d) all of theses
63. “Sound waves” cannot, passes?
(a) Air
(b) Water
(c) Vacuum
(d) None of these
64. Human ears, have_________________distinct, parts?
(a) 3
(b) 4
(c) 6
(d) 5
65. Speed ,sound_____________in air increase, in temperature?
(a) Increases
(c) Remain same
(b) Decreases
(d) None of theses
66. Speed of, sound in Iron, is?
(a)1530 M/s
(b) 3150 m/s
(c) 1503m/s
(d) 5130 m/s
67. The sound is, a form of energy, which travels through, any medium, as?
(a)Longitudinal
(b) Refraction
(c) Turnovers
(d) Compression
68. Over_______________________communication, satellites have been, launched since, 1957?
(a)100
(b) 200
(c) 300
(d) 600
69. “Satellite” is uses for, mapping, land?
(a) Sputnik
(b) Explorer
(c) Land sat
(d) Polar
70. “Geostationary” orbit, is above?
(a) North Pole
(b) Equator
(c) South pole
(d) None
71. Halley, comet appears, approximately every, years?
(a) 76
(d) 67
(b) 600
(c) 700
