Answer: 
Explanation:
The mean free path of an atom can be calculated using the following equation:
(1)
Where:
is referred to as the Universal gas constant
represents the absolute standard temperature
denotes the diameter of helium atoms
symbolizes Avogadro's number
indicates absolute standard pressure
<pFrom this, we can solve for
using
(1), aiming to determine the radius
of the helium atom:
(2)
(3)
(4)
If the radius equals half of that diameter:
(5)
Eventually:
(6)
(7)
Nonetheless, we were tasked with finding this radius in nanometers. Knowing 
:
(8)
Ultimately:
Represents the radius of the helium atom in nanometers.
In terms of light energy, a higher frequency corresponds to increased energy within the light.
We establish that frequency is essentially the inverse of wavelength:
frequency = 1 / wavelength
Calculating frequencies:
f UVA = 1/320 to 1/400
f UVA = 0.0031 to 0.0025
f UVB = 1/290 to 1/320
f UVB = 0.0034 to 0.0031
Since UVB occupies a higher frequency range, it consequently possesses greater energy than UVA.
Answer:
At this position, the magnetic field equals ZERO
Explanation:
The magnetic field produced by a moving charge is described as
Here, we determine the direction of the magnetic field using
Thus, we find
Leading to a magnetic field of ZERO
Consequently, when the charge moves in the same line as the given position vector, the magnetic field will be nonexistent
