101. The principle underlying a microwave oven is
(A) Microwaves are similar to thermal radiation.
(B) Microwaves vibrate the water molecules in food thereby generating heat.
(C) The heat generated by nuclear power
(D) Not fully understood
Correct Answer: [B] Microwaves vibrate the water molecules in food thereby generating heat..
102. Basically domestic electric wiring is a
(A) Combination of series and parallel connections.
(B) Series connection
(C) Parallel connection
(D) None of the above
Correct Answer: [C] Parallel connection.
103. The production of shadow proves that
(A) Light is a type of particle.
(B) Light does not diffract
(C) Light travels approximately is straight lines.
(D) Light is an electromagnetic wave
Correct Answer: [C] Light travels approximately is straight lines..
104. Which surface is a good absorber of heat?
(A) White smooth surface
(B) Black smooth surface
(C) White rough surface
(D) Black rough surface
Correct Answer: [D] Black rough surface.
105. Hubble is a
(A) Space telescope
(B) Star
(C) Nuclear weapon
(D) Musical instrument
Correct Answer: [A] Space telescope.
106. A small quantity of water is placed in a small cavity made in a block ice 0°C. What will happen to the water?
(A) The temperature of the water will decrease to 0°C but it will not freeze.
(B) The water will freeze to ice if the block of ice is large compared to the mass of water.
(C) The water will freeze to the ice at 0°C.
(D) There will be no change in the temperature of the water
Correct Answer: [A] The temperature of the water will decrease to 0°C but it will not freeze..
107. Of the following which is different from the others?
(A) X-rays
(B) Thermal electrons
(C) Cathode rays
(D) Photoelectrons
Correct Answer: [A] X-rays.
108. If a red light is used to illuminate a green leaf and a red flower, it will appear as
(A) Black leaf and red flower
(B) Black leaf and black flower
(C) Green leaf and red flower
(D) Red leaf and red flower
Correct Answer: [A] Black leaf and red flower.
109. The specific resistance of a conductor depends on its
(A) Temperature
(B) The shape of the cross-section
(C) Length
(D) Width
Correct Answer: [A] Temperature.
110. The material used for safety from nuclear radiation is
(A) Iron
(B) Lead
(C) Copper
(D) Platinum
Correct Answer: [B] Lead.
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