Multiple choice

Which of the following statements is correct?

  1. Carbon dioxide allows the earth to radiate heat rapidly at night.

  2. Percentage of carbon dioxide in air varies form 3% to 4%.

  3. Argon is a noble gas which is used for filling electric bulbs.

  4. A combustible substance combines with nitrogen to liberate heat energy.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Argon is used to fill light bulbs to inhibit the evaporation of the tungsten filaments and increase bulb life.

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