Answer:

Explanation:
The work function of the metal corresponds to the minimum energy needed to extract a photoelectron from the metal. In this case, it is:

So, the energy of the incoming photon hitting on the metal must be at least equal to this value.
The energy of a photon is given by

where
h is the Planck's constant
c is the speed of light
is the wavelength of the photon
Using
and solving for
, we find the maximum wavelength of the radiation that will eject electrons from the metal:

And since
1 angstrom = 
The wavelength in angstroms is

Answer:1). Distance of far point x=0.9m
Therefore, since the image is virtual
-f=-x = -0.9m
Power of the concave lenses = 1/f = 1/-0.9
= -1.11D
2 ) near point is 21cm = 0.21m
Power = 4-1/near point
= 4/0.21
= 14.2D.
Answer:

Explanation:
Given that

We know that acceleration a given as




We know that



So the magnitude of force F

Replacement teeth were made even back then out of primitive materials, and pig hair was used like floss
The correct answer is the Soccer ball is 3.2 plus 5 that’s your answer.