Is Light Reflected or Refracted?
1.When light propagates from a material with a given index of refraction into a material with a smaller index of refraction, the speed of light: a)DECRESES b)increses c)remains constant? 2.What is the minimum value that the index of refraction can have 0, +1,-1 between 0 and 1? 3.Now consider a ray of light that propagates from water (n=1.33) to air (n=1). If the incident ray strikes the water-air interface at an angle angle 1 equals / 0, which of the following relations regarding the angle of refraction, angle2, is correct? 4. A ray of light that propagates from air (n=1) to any one of the materials listed below. Assuming that the ray strikes the interface with any of the listed materials always at the same angle , in which material will the direction of propagation of the ray change the most due to refraction? a) ice (n=1.309) b)water (n=1.333) c)turpentine (n=1.472) d)glass (m=1.523) e)diamond (n=2.417)
Why does a ray of light not refract / bend when it passes through at glass prism at a angle of 90 degrees?
If you think of a plane landing on water, you can imagine that as soon as a part of it touched the water, it would tend to slow down. Of course, the plane is a single object, so a part cannot slow down, but it can create a force that 'turns' the plane - that changes the direction of the plane. If you imagine it you will see that the plane will always rotate so that it is pointing more sharply downwards, as long as the force from the water is asymmetrical - is not on the axis of the direction of travel. This only happens when the force on the plane is NOT a normal force. When it is a normal force, there is no angular moment , and the plane simply decelerates without changing direction. In the propagation of a wave,you have a vaguely similar effect. the details are not so simple, but perhaps this analogy will suffice for you.
Does the angle of refraction equal 0 degrees when a light ray enters one medium from another along the normal?
Yes. However, one can’t use numerical division to prove it.Snell’s Law for refraction is:n sin(θ) = n’ sin(θ’)where − π/2≤θ, θ’≤+π/2, θ is the angle of incidence, θ’ is the angle of refraction, 0
How do lenses refract light?
One of the properties of transparent materials is their 'index of refraction' (IOR), which is a measurement of the amount that light slows down on entering that material. It's true; the speed of light is not constant, just the speed of light *in vacuum*. Since the speed of light in vacuum is the fastest speed, vacuum has an index of 1.0. In comparison air has an index of 1.0003 or something very slightly higher than 1; water's index is about 1.33; ice is 1.309; Pyrex glass is 1.474; polycarbonate plastic is 1.59;cubic zirconia is 2.17 and diamond is 2.417. Diamond has the highest known IOR, which accounts for its 'fire' and brilliance. Okay, so various materials slow down light various amounts. What happens when a light wave passes from one material to another? If the light arrives at 90° to the surface (known as the 'normal' of the surface) there is no visible difference. But things get interesting when light arrives at an angle to the surface. Passing from a low-index environment (say, air for example) into a high-index environment makes the light slow down. But since the light continues to arrive at the same speed, the light waves get shorter in the high-index material. The result is a bent light beam; in high index material the light's path is closer to the normal than it is on the side with low index material. You can see this effect by placing a drinking straw in a glass of water. Look at the straw from above and you will notice the straw looks bent at the water's surface, and the straw underwater looks shorter than it does in the air. Lenses have carefully formed curved shapes that take advantage of refraction to bend light differently depending on where it encounters the lens. Since it curves the light in a controlled variable manner, it can focus or otherwise alter the pattern of light waves. There are other factors that affect lenses too. One of them is the colour of the light; red light bends a different amount than blue. This is what causes prisms to break up white light into separate colours. When a lens causes dispersion like this it is called 'chromatic aberration', (which sounds like wearing a green jacket with purple pants, but it's not). Dispersion in diamonds is very noticeable because it is increased by the very high IOR and by internal reflection whic increases the length of the light path.
Why does a ray of light remain undeviated on passing through the optical centre of a lens?
How can it be explained using the laws of refraction that a light through optical centre of a lens passes undeviated?If we assume the portion of the lens in the middle to be made of even number of alternately place up and down prisms, then it's clear, but why can the number of prisms not be odd?Look at the lens as a slab of finite thickness. In a small vicinity around its center we may consider its opposing surfaces as parallel to each other. A ray incident on this area, at any angle, will be refracted twice at parallel interfaces. Therefore it will emerge on the other side of the lens on a direction slightly displaced, but parallel to the incident one. Since the parallel displacement is tiny as long as the lens is not too thick, it looks like the ray passes through the center undeviatedTruth is that the light does not pass through undeviated,we just assume it passes through undeviated, this is because we make the thin lens assumption.we assume that the lens we are dealing with is thin and in such lenses,when light is directed towards the optic centre the light ray refracts once while entering the lens and the second time while exiting the lens but since the lens is thin the light wouldn't have travelled a large distance in the lens therefore when the light exits the lens the amount of deviation from the path light would have taken if there were no lens would be very less( very negligible ) ............butto keep things simple we say just say that the light ray passes through undeviated.But keep in mind , as the lens gets thicker and thicker the deviation will become larger. ;)The middle part of the lens will just act as a rectangular glass slab. We may verify it by cutting the lens horizontally. Now we know that rectangular glass slab refract light in such a way that emergent is parallel to incident. Actually the same happens when the ray passes through optical centre. This can be observed in a thick lens. In thin lenses the perpendicular distance between extended incident ray and extended emergent ray is negligible. So we can say that light ray passes through optical centre without deviation.Actually the same happens when a ray of light passes through optical centre the perpendicular distance between extended incident ray and extended emergent ray is negligible so...we can say that the ray which passes through the optical centre is undeviate.Thank you.
Refracted Ray and Critical Angle Question?
The critical angle for total internal reflection at a liquid-air interface is 42.5 degrees. a. If a ray of light traveling in the liquid has an angle of incidence of 35 degrees at the inference, what angle does the refracted ray in the air make with the normal? b. If a ray of light traveling in air has an angle of incidence of 35 degrees at the interface, what angle does the refracted ray in the liquid make with the normal? c. Describe a picture of both cases with their rays. Thank you very much to those who can answer this question.
When a light ray is refracted from one medium to another, the wavelength changes from 450 nm to 300 NM. What is the critical angle for a ray from second medium to first medium?
Its difficult to solve in the editor please refer the picture below.
What would be the path of a single ray of light passing through a right angled prism?
Light is incident normally (angle of incidence=0) to the surface of prism, so it doesn't refract or it goes undeviated, similar is the case for second surface.
How is light ray refracted if it is incident normally to the interface of two media?
It will propagate in same direction as incident ray of light.This can explained by wave nature of light :When light ray strikes a surface perpendicularly, all its parts enter the medium at the same time. So, all the parts of light will have a change in speed at the same time.So, there will be no bending but only change in speed of light ray.Hope it helps!!
Is there an agle at which light rays in air meeting the air-water boundary will totally reflect?
Snells Law says n1*sin(theta1) = n2*sin(theta2). The index of refraction of air is about 1 and the index of refraction of water is about 1.33. To be totally reflected the angle of refraction must be more than 90 degrees. Hence 1*sin(theta1) = 1.33*sin(90) = 1.33*1 = 1.33 no angle will have a sin greater than 1. Hence light coming in at any angle will be refracted greater than 90 degrees so light will not be totally internally reflected going from air to water -- total internal refraction only can occur when coming for a higher index of refraction to a lower one.