Answer:
Explanation:
Based on the wave model of light, physicists predicted that increasing light amplitude would increase the kinetic energy of emitted photoelectrons, while increasing the frequency would increase measured current.
Contrary to the predictions, experiments showed that increasing the light frequency increased the kinetic energy of the photoelectrons, and increasing the light amplitude increased the current.
Based on these findings, Einstein proposed that light behaved like a stream of particles called photons with an energy of \text{E}=h\nuE=hνstart text, E, end text, equals, h, \nu.
The work function, \PhiΦ\Phi, is the minimum amount of energy required to induce photoemission of electrons from a metal surface, and the value of \PhiΦ\Phi depends on the metal.
The energy of the incident photon must be equal to the sum of the metal's work function and the photoelectron kinetic energy:
Answer:

Explanation:
n = Order = 1
c = Speed of light = 
f = Frequency = 
= Angle = 
Lattice spacing is given by

The lattice spacing of the crystal is 
At the highest point of motion the ball comes to rest momentarily,but it is being pulled down due to the effect of gravity,so its net acceleration is downwards. So,just after that point,it starts falling downwards.
Answer:
I don't know if it is correct or not.