61. Blood is a colloid. In it, cells are suspended in a liquid called plasma. What is the process of separation of a substance in a colloid called?
(a) Dialysis
(b) Endoscopy
(c) Biopsy
(d) Transparency
62. What is the artificial earth-orbiting object used to relay radio signals between points on Earth called?
(a) Artificial satellite
(b) Communication Satellite
(c) Satellite
(d) Oscillating Satellite
63. At which height above the equator are the orbits of most communication satellites located?
(a) 30,000 km
(b) 33,900 km
(c) 20,000 km
(d) 35,900 km
64. When two or more elements are joined together, they are called:
(a) Conductor
(b) Solid
(c) Physical Sciences
(d) Copper
65. The mass of an object divided by its volume is called:
(a) Density
(b) Thickness
(c) Weight
(d) Gravity
66. Which substance is used to remove dirt and grease but, unlike soap, does not form a thin layer of scum on the surface of water?
(a) Detergent
(b) Washing powder
(c) Petrol
(d) Caustic Soda
67. A beam of white light is broken up into its component colors when it passes through a triangular glass prism. What is this optical phenomenon called?
(a) Reflection
(b) Refraction
(c) Dispersion
(d) Spectrum
68. An element is made up of many atoms. In a compound, the atoms of each element are joined together to form a molecule. Water is also a compound. Which elements does it contain?
(a) Hydrogen and oxygen
(b) Hydrogen and Carbon
(c) Carbon and oxygen
(d) Helium and Oxygen
69. What does the term “concave” of a surface mean?
(a) Curving inward
(b) Curving outward
(c) Both of them
(d) None of them
70. Steam in a bathroom cools on the cold walls and windows to form trickles of water. What is this change of a gas into liquid when it is cooled called?
(a) Condensation
(b) Fog
(c) Smog
(d) None of these