In epidemiology, incidence is a measure of the probability of occurrence of a given medical condition in a population within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator.
High!
I have a EM plane wave hitting normally a surface dividing universe in media 1 and 2, both without losses.
So we have incident, reflected and transmitted waves.
It's a simple exercise in which you are given the basic data about two media and wave incident amplitude H in medium 1.
I get...
Hello,
Something has made me confused after studying the Snell equations these days. Regarding the Balanis Advanced engineering electromagnetic( the pages have been attached), and based on that the reflection and transmission coefficient can be complex I need to rewrite the (5-23a) again...
the angle of incidence at A is 40°, then why did the answer key say "angle of incidence at A is just less than 90°". it is obvious that 40° is quite far from 90° right?
I'm not sure where to start on this as I've only used Fraunhofer when it involves slits, not mirrors. Would I say it was a single slit problem so that D = width of slit (but this doesn't make sense to me because the light is reflecting not transmitting? Or an infinitely narrow slit hence nothing...
Summary:: A plane wave incident upon a planar surface - determining polarization, angle of incidence etc.
𝐄̃i = 𝐲̂20𝑒−𝑗(3𝑥+4𝑧) [V. m−1 ]
is incident upon the planar surface of a dielectric material, with εr = 4, occupying the halfspace z ≥ 0.
a) What is the polarisation of the incident wave...
Hello everybody,
I have to find the amplitudes of a wave that goes through 4 different mediums in terms of ##E_0##, suffering reflection in the first three but not the last one. I calculated the corresponding reflection indexes of the three mediums (all of them real).
Following calculations, I...
I am a using a mirror to reflect an image at an angle of incidence of 10 degrees. The mirror is also at an angle of incidence of approximately 30 degrees from the viewer and it creates undesired reflections when looking at the mirror. Here is a diagram illustrating the situation.
I am looking...
I for one don't see how ##\sin \theta_t \gt 1## is possible, even when you extend into the complex numbers. Is there even a way to order the complex numbers? Does he mean to say that the magnitude is greater than 1?
Anyway here's my attempt at interpreting what my instructor is trying to say...
I'd first like to preface this post with the "right answer" per wikipedia (I've seen the same answer elsewhere on more reputable websites)
The thing I find trouble some is the cross terms such as ##n_2 \cos \theta_i## where indices of refraction are "mixed with the other angle".
I have...
When light, traveling through a rarer medium, gets reflected off at an interface with a medium of higher refractive index, it suffers a phase shift of half-wavelength. Now if it was normal incidence, the phase-shifted light would retrace its path. Does that mean the wave would cancel out?
Homework Statement
Light of free-space wavelength λ0 = 0.87 μm is guided by a thin planar film of thickness d = 3.0 μm and refractive index n1 = 1.6, surrounded by a medium of refractive index n2 = 1.4
critical angle = 61.04°
n0 = 1.00
(a) Determine (i) the angle of incidence θ and (ii) the...
Hi. I'm reading a paper "Transmission of light through a single rectangular hole in a real metal" and the author refers to the incident light shown below as "p-polarized" without further specification.
Note that ax > ay. Is there any convention in regarding a certain polarization as...
Homework Statement
A light ray shines from a diamond (n = 2.42) into water (n = 1.33), and no refraction occurs. What is the angle of incidence?
0°30°45°60°
Homework Equations
sin θc = nr/ni ?
The Attempt at a Solution
I thought that by finding the critical angle then anything above that...
Hi all,
I have some difficulties understanding a formula for calculating the incidence angle for incoming solar radiation on a sloping surface. I found that:
angle of incidence calculated as cos(j) = sin((pi/2)-surface slope)*sin(altitude angle) + cos((pi/2)-surface slope)*cos(altitude...
<Moved from a homework forum. Template removed.>
I can't find any documentation on how to do this. I remember in linear algebra how to find the incidence matrix of an electrical network of purely resistors. Put how do I find it of a RLC circuit with resistors, inductors, and capacitors? I can't...
Good afternoon! Please help me figure out the mathematics of this simple plane wave question!
1. Homework Statement
2. Homework Equations
n1*sin(theta1)=n2*sin(theta2)
The Attempt at a Solution
I need help calculating the angle of incidence.
I found the propagation vector for incidence...
Homework Statement
A plate is subjected to rays from a light source located 35 degrees above the horizon. The plate itself is tilted 12.5 degrees around its vertical axis reducing the exposure to the light source.
Find the incidence angle between the light source and the front face of the...
Homework Statement
“The risk of celiac disease at 5 years of age was 12.1% (95% CI, 9.2 to 15.0).”
The question is: what do they mean with risk
a,incidence rate
b.cumulative incidence
c.attributive risk
d.population atrributive risk
Homework EquationsThe Attempt at a Solution
I don't...
Hello!
Let's consider a plane wave represented by a ray, propagating in a 2D dielectric slab. It has a medium with refractive index n_1 as its core and a medium with refractive index n_2, n_2 < n_1, as its cladding. In order for this ray to represent a mode, it must satisfy two conditions:
-...
I have a conceptual doubt. pl help me clarify it:
What will happen if angle of incidence on a glass slab is 0? will refraction take place, or reflection, or both?
I'm trying to understand the solution to an exercise.
The solution claims that that the absorbed power of a black body from sunlight with an angle of incidence of ##30^\circ## is
##P=P_0\cos(30^\circ)##
The reasoning here being to take the component orthogonal to the surface.
However what...
Assume a flat one square foot vertical plate attached 6 feet up, outside on a wall.
Dozens of yards away are various solar reflectors angled to reflect sunlight onto that plate.
Problem is, the plate requires to be only struck straight on at a 0 degree angle of incidence.
And, all the...
The radiation pressure for a perfect mirror is given by:
P = 2 Ef/c * cos²(θ)
Where Ef is the energy flux per area (Power/A), and θ is the angle of incidence
(from: https://en.wikipedia.org/wiki/Radiation_pressure)
Since force due to pressure is F = PA, force due to radiation pressure become...
Homework Statement
A ray of light falls on the surface AC of a prism with a straight angle and with two sides equal. For which incidence angle the ray won't come out of the surface AB. The index of refraction for the prism is n=2.
Homework Equations
sina/sinb=n2/n1
The Attempt at a Solution...
Homework Statement
When the incidence angle is equal to the angle of refraction?
Homework Equations
sina/sinb=n2/n1The Attempt at a Solution
I think as a=b => sina=sinb => n1=n2. We should have the same environment? But is that refraction?
Hello PF users hope all is well!
I need a reminder of the formulas needed in order to get
"Sine of angle of incidence"
"Sine of angle of refraction"
And "Index of refraction".
The only information I have available now is
"Angle of incidence" And "Angle of refraction"
I'm guessing...
Hello!
In this previous post, most replies point out that it is not possible to predict the angle of refraction (and so the frequency) at a certain interface, given the wavelength of the original signal.
In particular,
But when dealing with optical waveguides, it seems to be different. I am...
I understand that the refractive index of different materials affects the speed of light but does light change speed in glass when entering from air at different angles of incidence?? if not what causes the variation in lateral displacement?
Hello everyone,
I am trying to figure out how to explain an aspect of this question to my students, but cannot seem to recall the geometry that explains the textbook's approach.
In the figure below, for part (b) of the question, we are using the angles of refraction at the left boundary to...
Hello!
This post is strictly related to my previous one. Let's consider the same context and the same image. Regarding the oblique incidence of a wave upon an interface between two dielectric, all the texts and all the lectures write an equation like the following:
e^{-j k_1 y \sin \theta_i} +...
Consider the problem shown in the "wave_incidence_1.png" attached image. An electro-magnetic wave is traveling towards an interface between its current medium and a new medium, which has a refractive index n_2 \neq n_1. The interface is represented by the (x,y) plane.
The electric field...
Homework Statement
I've not been able to do this question for years so I'd really appreciate some help.
Light is normaly incident from a medium 1 with impedance Z1 through a layer of medium 2 of thickness L and impedance Z2 into medium 3 of impedance Z3. Obtain an expression for the total...
Homework Statement
We have a honeycomb lattice. There is an incident wave of 400 nm, whose wavevector has an angle of 75 degree with the surface's normal. This problem is similar to LEEDS ( low energy electron diffraction).
Homework Equations
What is the condition of diffraction i.e. which...
Assume a 2D problem. Given a linear antenna array, let's say 3 antennas distributed around the z axis, how could we extract the incidence angle of the received wave?
Having 3 antennas equally spaced by λ/2 in the z axis and connected to each other, the result gain would be a function of ϑ (angle...
My understanding is that the seasonal variation in temperature, amongst many other things, is a reflection of the Earth's tilt.
Simply put, at the equator, sun rays fall "straight down" (100% vertical), and all of their energy hits the surface of the Earth. At different latitudes, these rays...
I am trying to write a java code where the user inputs the height at which a solid body approaches a sphere of radius R and outputs the angle ##\theta## at which the body bounces off the sphere.
I have all my code written is just that I don't know how to derive the equation that calculates the...
I want to why in ray optics. Angle between incident ray and reflecting surface normal is equal to angle between reflected ray and reflecting surface normal. Simply why angle of incidence is equal to angle of reflection?
Homework Statement
Derive an equation relating the angle of incidence and the angle of refraction as light travels from air to glass. Do it in the form of Θ2/Θ1 = expression
Homework Equations
I think the equation to use here is Snell's law. Right?
n1sinΘ1 = n2sinΘ2
n1 = nair =...
Homework Statement
A ray of light incident on a glass sphere (refractive index sqrt 3) suffers total internal reflection before emerging out exactly parallel to the incident ray. What was the angle of incidence?
μ = refractive index of the glass sphere, i = angle of incidence, r = angle...
How to define the plane of incidence for normal incidence of a plane polarized wave?
Is the reflection coefficient defined by ordinary, extraordinary, or the combination of both waves?
Thanks for the help!
Homework Statement
The direction of the ray of light enters equilateral 60° glass prism normal to the surface as shown in attached image
refracted index of the prism material for the violet light is 1.651
(a) What is the angle of incidence on the surface A-B?
(b) Does total internal...
The question asks to use Fresnel's equations at normal incidence to find the ratio of the refractive indexes of the two materials. We are told equal energy is transmitted and reflected and that both media are non-magnetic and non-conducting dielectrics.
So I know that the ratio of Er/Ei and...
Hello everyone,
I see that economists define a formula to calculate how the tax is shared between consumers and suppliers.
They call it "Pass-thorugh" fraction:
Customers share = (-PED)/(PES-PED)
Suppliers share = PES/(PES-PED)
However I see this doesn't work when I use it with...
Firstly, I'm sorry if this is incorrect or if there is a specific place for such questions but as this is neither a problem posed to me, nor something that has been taught - I have little background with which to work with but it is something I need to do for my ERT and 2 maths teachers have...
I don't really know too much about the human body, but this is my rough understanding of how vision works: light comes from a source, like the sun, it hits an object, and then if it's of the right frequency it's reflected by the object and then enters one of your two eyes, where it is refracted...
Homework Statement
I have a problem with the question in the attachment below. I have no idea on how to proceed as I thought that the ray of light would continue to travel in a straight line with no refraction whatsoever.
Homework Equations
n1sinθ1=n2sin2
The Attempt at a...