Answer:
The minimum thickness = 83.92 nm
Explanation:
The relation between the wavelength in a particular medium and refractive index 
where ;
= wavelength of the light in vacuum
n = refractive index of medium with respect to vacuum
For one phase change :

Replacing 1.43 for n and 480 nm for λ; we have:

t = 83.92 nm
Thus; the minimum thickness = 83.92 nm

- The angle between the two vectors is 90° .

- The dot product of two vectors .
- The cross product of two vectors .

⚡ Let
and
are the two vectors .
✍️ We have know that,

Where,



[1] The dot product of two vectors is “ <u>0</u> ” .
✍️ We have know that,

Where,



[2] The cross product of two vectors is “ <u>ab</u> ” .
The energy carried by a single photon of frequency f is given by:

where

is the Planck constant. In our problem, the frequency of the photon is

, and by using these numbers we can find the energy of the photon:
Complete question:
Two 10-cm-diameter charged rings face each other, 21.0 cm apart. Both rings are charged to +40.0 nC. What is the electric field strength at the midpoint between the two rings ?
Answer:
The electric field strength at the mid-point between the two rings is zero.
Explanation:
Given;
diameter of each ring, d = 10 cm = 0.1 m
distance between the rings, r = 21.0 cm = 0.21 m
charge of each ring, q = 40 nC = 40 x 10⁻⁹ C
let the midpoint between the two rings = x
The electric field strength at the midpoint between the two rings is given as;

Therefore, the electric field strength at the mid-point between the two rings is zero.
In the motion of the medium particles in a longitudinal wave, the medium vibrates parallel to the direction of the wave.
<h3>What is a longitudinal wave?</h3>
A longitudinal wave is a wave that is transversing along the length. When the displacement of medium and travel of wave is the same in that condition wave is known as the longitudinal wave.
It requires some medium to travel. A mechanical and sound wave is an example of a longitudinal wave.
Hence in the motion of the medium particles in a longitudinal wave, the medium vibrates parallel to the direction of the wave.
To learn more about the longitudinal wave refer to the link;
brainly.com/question/8497711