141. Minimum number of unequal vectors which can give zero resultant are
142. Identify the vector quantity from the following
143. Planets do not twinkle because
- A. they emit light of a constant intensity
- B. their distance from the earth does not change with time
- C. they are very far away from the earth resulting in decrease in intensity of light
- D. they are nearer to earth and hence we receive a greater amount of light and, therefore minor variations in the intensity are not
- Check Answer | Discussion
144. Light from the star, Alpha Centauri, which is nearest to the earth after the sun, reaches the earth in
145. Radiocarbon is produced in the atmosphere as a result of
- A. collision between fast neutrons and nitrogen nuclei present in the atmosphere
- B. action of ultraviolet light from the sun on atmospheric oxygen
- C. action of solar radiations particularly cosmic rays on carbon dioxide present in the atmosphere
- D. lightning discharge in atmosphere
- Check Answer | Discussion
146. Mach number is used in connection with the speed of
147. One watt-hour is equivalent to
148. Lux is the SI unit of
149. Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?
150. One nanometer is equal to
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