| 271. | What is the mineralogical composition of diamond? |
A. Carbon | |
B. nitrogen | |
C. nickel | |
D. Zinc |
| 272. | Carbon dating is used to determine the age of |
A. fossil | |
B. plants | |
C. rocks | |
D. none of the above |
| 273. | The following non-metallic element has metallic luster – |
A. Sulphur | |
B. phosphorus | |
C. iodine | |
D. Boraun |
| 274. | Where the ozone layer is mainly located, that is – |
A. troposphere | |
B. stratosphere | |
C. mesosphere | |
D. ionosphere |
| 275. | Who among the following discovered heavy water? |
A. Heinrich Hertz | |
B. h p ure | |
C. g mendel | |
D. Priestley |
| 276. | Which one of the following is also called stranger gas? |
A. argon | |
B. `neon | |
C. geneon | |
D. nitrous oxide |
| 277. | Which of the following is a semiconductor? |
A. plastic | |
B. aluminum | |
C. wood | |
D. germanium |
| 278. | The main gaseous pollutant of thermal power is – |
A. hydrogen sulfide | |
B. ammonia | |
C. nitrogen dioxide | |
D. sulfur dioxide |
| 279. | is in the tip of the matchstick |
A. phosphorus pentoxide | |
B. white phosphorus | |
C. red phosphorus | |
D. phosphorus trichloride |
| 280. | Diamond and graphite are |
A. misshapen | |
B. isomorphic | |
C. isomer | |
D. isobars |