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:
D
Explanation:
The answer is Niels Bohr's planetary model, the difference between this model and all of the other models is that the Bohr's PM Is more of layers of
Nucleus - Protons and Neutrons
Electron Orbital - Period 1 Elements
2 electrons
Electron Orbital - Period 2 Elements
8 electrons
Electron Orbital - Period 3 Elements
8 electrons
If that made sense-
Answer:
Explanation:
The work done is defined as the product of force applied in the direction of displacement and the displacement.
W = F x d x Cosθ
where, F is the force applied, d be the displacement and θ be the angle between the displacement and force.
For the normal forces, the angle between the displacement and the force applied is 90 degree, and the value of Cos 90 is zero, so the work done is zero.
Answer:
The magnetic force on the section of wire is
.
Explanation:
Given that,
Current 
Length = 0.750 m
Magnetic field 
We need to calculate the magnetic force on the section of wire
Using formula of magnetic force


Since, 

Hence, The magnetic force on the section of wire is
.
Answer:
A) v = 40 m / s, B) v_average = 20 m / s
Explanation:
For this exercise we will use the kinematics relations
A) the final velocity for t = 5 s and since the body starts from rest its initial velocity is zero
v = vo + a t
v = 0 + 8 5
v = 40 m / s
B) the average velocity can be found with the relation
v_average = vf + vo / 2
v-average = 0+ 40/2
v_average = 20 m / s