Question

Assertion: A helium filled balloon does not rise indefinitely in air but halts after a certain height.
Reason: Viscosity opposes the motion of the balloon.

A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C) Assertion is correct but Reason is incorrect
D) Assertion is incorrect but Reason is correct

Answer 1

The air goes on becoming less dense as the height increases.

Complete step by step answer:
The balloon initially rises in air as a result of the burden of the displaced air (in alternative words) rise is larger than the burden of the argonon and also the balloon. Since the density of air decreases with height so the balloon halts once an explicit height wherever the density of air is such the burden of air displaced is simply up to the burden of argonon gas and also the balloon. That is the reason for the world wide web force performing on the balloon is zero and also the balloon stops rising.
Therefore, the correct option is C) Assertion is correct but Reason is incorrect

Note: Altitude is height on top of water level. The density of air decreases with height. These squares measure 2 reasons: at higher altitudes, there's less air pushing down from on top of, and gravity is weaker farther from Earth's center. therefore at higher altitudes, air molecules will unfolded additional, and air density decreases. Like density, the pressure of the air decreases with altitude. there's less air pressing down from on top of the upper up you go.