A helium-filled weather balloon has a volume of 200 L when it is on the ground, where the pressure is 1 atm. What will its volume be at a height of 2 km, where its pressure is 0.785 atm, assuming that the temperature remains constant?

Explanation:

power of a heating element = V² / R where V is voltage and R is resistance

putting in the values

5200 = 75² / R

R = 1.082 ohm

Formula for resistance

R = ρ L / S , ρ is resistivity , L is length and S is cross sectional area

1.082 = 5 x 10⁻⁷ x L / (3.83 x 10⁻⁶)

L = 8.29 m

b )

power of a heating element = V² / R , R is new resistance

5200 = 120² / R

R = 2.77 ohm

R = ρ L / S , ρ is resistivity , L is length and S is cross sectional area

2.77 = 5 x 10⁻⁷ x L / (3.83 x 10⁻⁶)

L = 21.22 m