A balloon filled with helium rises in air because
A. Air exerts an upward force on the balloon
B. The balloon is weightless
C. Helium is less dense than air
D. Helium pushes down on the air below the balloon
Answer: Option C
A. Air exerts an upward force on the balloon
B. The balloon is weightless
C. Helium is less dense than air
D. Helium pushes down on the air below the balloon
Answer: Option C
Which of the following phenomenon is considered responsible for Global Warming?
A. Greenhouse effect
B. Fire in coal mines
C. Dry farming
D. Monsoon
E. Trade winds
The nucleus of an atom consists of
A. electrons and neutrons
B. electrons and protons
C. protons and neutrons
D. All of the above
The number of moles of solute present in 1 kg of a solvent is called its
A. molality
B. molarity
C. normality
D. formality
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