Answer: 
Explanation:
The kinetic energy of an electron
is given by the following equation:
(1)
Where:

is the momentum of the electron
is the mass of the electron
From (1) we can find
:
(2)
(3)
Now, in order to find the wavelength of the electron
with this given kinetic energy (hence momentum), we will use the De Broglie wavelength equation:
(4)
Where:
is the Planck constant
So, we will use the value of
found in (3) for equation (4):
(5)
We are told the wavelength of the photon
is the same as the wavelength of the electron:
(6)
Therefore we will use this wavelength to find the energy of the photon
using the following equation:
(7)
Where
is the spped of light in vacuum
Finally:
Answer:

Explanation:
A charge located at a point will experience a zero electrostatic force if the resultant electric field on it due to any other charge(s) is zero.
is located at the origin. The net force on it will only be zero if the resultant electric field intensity due to
and
at the origin is equal to zero. Therefore we can perform this solution without necessarily needing the value of
.
Let the electric field intensity due to
be +
and that due to
be -
since the charge is negative. Hence at the origin;

From equation (1) above, we obtain the following;

From Coulomb's law the following relationship holds;

where
is the distance of
from the origin,
is the distance of
from the origin and k is the electrostatic constant.
It therefore means that from equation (2) we can write the following;

k can cancel out from both side of equation (3), so that we finally obtain the following;

Given;

Substituting these values into equation (4); we obtain the following;


Answer:
A vacuum would have been created. I hope this helps have a great day
Answer:
Explanation:
In case of diffraction , angular width of central maxima =2 λ/d
λ is wave length of light and d is slit width
In case of interference , angular width of each fringe
= λ /D
D is distance between two slits
No of interference fringe in central diffraction fringe
=2 λ/d x D/λ = 2 x D /d = 2 x .24/.03 = 16.