A toy balloon originally held 1.0 gm of He gas and had a radius 10 cm. During the night , 0.25 gm of the gas effused from the balloon. Assuming ideal gas behaviour , under these constant P andT conditions, what was the radius of the balloon the next morning.

A spherical balloon is filled with 4500p cubic meters of helium gas. If a leak in the balloon causes the gas to escape at the rate of 72pi cubic meters per minute, then the rate (in meters per minute) at which the radius of the balloon decreases 49 minutes after the leakage began is (1) 9/7 (2) 7/9 (3) 2/9 (4) 9/2

Calculate the work done when done when 1.0 mol of water at 373K vaporises against an atmosheric pressure of 1.0atm . Assume ideal gas behaviour.

A conducting bolloon of the radius a is charged to potential V_(0) and held at a large height above the earth ensures that charge distribution on the surface of the balloon remains unaffected by the presence of the earth. It is connected to the earth through a resistance R and a value in the balloon is opened . The gas inside the balloon escapes from value and the size of the balloon decreases. The rate of decrease in radius of the balloon is controlled in such a manner that potential of the balloon remains constant. Assume the electric permittivity of the surrounding air equals to that of free space (epsilon_(0)) and charge cannot leak to the surrounding air. The rate at which radius r of the balloon changes with time is best represented by the equation

A certain balloon maintains an internal gas pressure of P_(0) = 100 k Pa until the volume reaches V_(0) = 20 m^(3) . Beyond a volume of 20 m^(3) , the internal pressure varies as P = P_(0) + 2 k (V - V_(0))^(2) where P is in kPa. V is n m^(3) and k is a constant (k = 1 kPa//m^(3)) . Initially the balloon contains helium gas at 20^(@)C , 100 kPa with a 15 m^(3) volume. The balloon is then heated until the volume becomes 25 m^(2) and the pressure is 159 kPa. Assume ideal gas behaviour fro helium. The work done by the balloon for the entire process in kJ is

An elasticized conducting band is around a spherical ballon . Its plane through the center of the balloon. A uniform nmagnetic field of magnitude 0.04T is directed perpendicular to the plane of the band. Air is let out of the balloon at 100 cm^(3) s^(-1) at an instant when the radius of the balloon is 10 cm . The induced emf in the band is

A gas filled freely collapsible balloon is pushed from the surface level of a lake to a depth of 50 m. Approximately what per cent of its original volume will the balloon finally have, assuming that the gas behaves ideally and temperature is same at the surface and at 50 m depth ?