Explanation:
Given that,
Wavelength of the light, 
Work function of sodium, 
The kinetic energy of the ejected electron in terms of work function is given by :

The formula of kinetic energy is given by :

Hence, this is the required solution.
Probably for the umbilical cord that connects babies (from their early stages in the womb to their removal) to their mothers. The cord is cut, forming the belly button. This is analogous to astronauts in space.
Answer:
The diameter of the piston of the players equals 55.136 cm.
Explanation:
from the principle of transmission of pressure in a hydraulic lift we have

Since the force in the question is the weight of the individuals thus upon putting the values in the above equation we get

Solving for
we get

The wavelength decreases to roughly half.
(The frequency roughly doubles.)