# Question about reflectivity and maximization of energy reflected

• LCSphysicist
In summary, the conversation discusses the necessary incident angle and orientation of the beam for maximum reflection off the surface of a pond with an index of refraction of 9.0. The solution involves making the dipole perpendicular to the plane of incidence and setting the incident angle to ##\pi/2##. It is also suggested to study Brewster's angle for further understanding.
LCSphysicist
Homework Statement
.
Relevant Equations
.
Imagine that we have a transmitter of microwaves that radiates a linearly polarized wave whose E field is known to be parallel to the dipole direction. We wish to reflect as much energy as possible off the surface of a pond (having an index of refraction of 9.0). Find the necessary incident angle and comment on the orientation of the beam.

I have solved it, but since the textbook has no solutions on it i would like to know if you agree with my answer:
Since for electric field perpendicular to the plane of incidence $$r_{per} = sin^2(\Delta \theta)/sin^2(\sum \theta)$$

And for electric field parallel $$r_{par} = tan^2(\Delta \theta)/tan^2(\sum \theta)$$

We have $$r_{par} = tan^2(\Delta \theta)/tan^2(\sum \theta) = r_{per} cos^2(\sum \theta)/cos^2(\Delta \theta) < r_{per}$$

So, since we want to maximize the reflected energy, we should make the dipole perpendicular to the plane of incidence.

The problem is about the angle of incidence. My answer would be something like:

"To got maximum reflection energy, make the dipole perpendicular to the plane of incidence, so that the electric field is also perpendicular to the plane. About the angle, make the incident angle of the wave ##\theta \to \pi/2##.

What do you think?

Delta2

## 1. What is reflectivity?

Reflectivity refers to the ability of a surface or material to reflect light or other forms of electromagnetic radiation. It is typically measured as a percentage, with higher values indicating a greater amount of reflected energy.

## 2. How is reflectivity related to energy?

Reflectivity is directly related to the amount of energy that is reflected by a surface. A material with high reflectivity will reflect more energy than a material with low reflectivity. This can have implications for energy efficiency and heat management in buildings and other structures.

## 3. How is reflectivity measured?

Reflectivity is typically measured using a device called a spectrophotometer, which measures the amount of light reflected by a surface at different wavelengths. This data is then used to calculate the reflectivity of the surface.

## 4. Why is maximizing energy reflected important?

Maximizing energy reflected can be important for a variety of reasons. In some applications, such as solar energy, it is desirable to have a high reflectivity in order to maximize the amount of energy captured. In other cases, such as in buildings, maximizing reflectivity can help reduce heat absorption and lower energy costs for cooling.

## 5. How can reflectivity be increased?

Reflectivity can be increased through a variety of methods, such as using reflective coatings or materials, or by altering the surface texture to increase the angle of reflection. In some cases, simply choosing a material with a higher natural reflectivity can also help to increase the overall reflectivity of a surface.

• Introductory Physics Homework Help
Replies
6
Views
642
• Introductory Physics Homework Help
Replies
15
Views
392
• Introductory Physics Homework Help
Replies
55
Views
3K
• Introductory Physics Homework Help
Replies
1
Views
512
• Introductory Physics Homework Help
Replies
16
Views
271
• Introductory Physics Homework Help
Replies
1
Views
805
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
20
Views
1K
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
7
Views
376