when sound enters from air or vice - versa, which physical quentity of the waves ramains unchanged ?

When sound enters water from air or vice-versa, which physical quantity of the waves remains unchanged?

When a copper sphere is heated, which physical quantity of the sphere will show maximum percentage change?

When light enters from glass to water, which of the following quantity remains unchanged ?

An open vessel has a temperature of TK. When the vessel is heated at 477^(@)C , three fifths of air in the vessel escapes out. What fraction of air in the vessel would have been expelled out if the vessel were heated at 900 K (assume that volume of the vessel remains unchanged on heating)-

When light moves from glass to air, the property of it which remains unchanged is

When an open vessel at 27^(@)C ws heated, three-fifths of the air is in escaped from it. If the volume of the vessel remained unchanged, calculate the temperature at which the vessel was heated?