Aballoon filled with helium gas has a volume of 500 ml at a pressure of 1 atm. the balloon is released and reaches an altitude of 6.5 km, where the pressure is 0.5 atm. if the temperature has remained the same, what volume does the gas occupy at this height?

The volume of the gas will be 1 L at a height of 6.5 km.

Since temperature is constant, we can use Boyle’s Law.

p₁V₁ = p₂V₂

p₂ = p₁ × V₁/V₂ = 500 mL × (1 atm/0.5 atm) = 1000 mL = 1 L

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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