What two things happen to a wave when it is refracted?

An object weighs 40n in air, weighs 20n when submerged in water and 30n when submerged in a liquid of unknown density. what is the density of the liquid?

Describe how the motion of a spring being pushed forward and backward is similar to the motion of air particles in a sound wave.

When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(ii) sulfate is reduced to lead at the cathode and oxidized to solid lead(ii) oxide at the anode. suppose a current of is fed into a car battery for seconds. calculate the mass of lead deposited on the cathode of the battery.