Physics

Why does the focal length of a lens increase when it is put in water?

Light changes direction when it goes from one medium to another for two reasons. One is because it is a wave and other is because the light travels different speeds in the two mediums.

Light travels the speed c in vacuum and it travels the slower speed 3/4c in water and even the slower speed 2/3c in glass.

When the lens is in air the difference in speed is 2/3c versus c. When it is in water the difference in speed is 2/3c versus 3/4c. The difference in speed is smaller when it is in water and so the light bends less. The light bending less corresponds to a longer focal length.

Which of the two has a greater power a lens of short focal length or a lens of large focal length?

A lens of short focal length has a greater power (than a lens of large focal length)

How focal length of a lens change when apparatus immersed in water?

Yes , because when lens is deeped in water its R.I changes & hence focal length is increased

How do you find the new focal length when the lence is put in to the water?

to find the new focal length when the lens is put into water it becomes the 4 times the focal length in air.

What is the focal length of a lens?

The focal length of a lens refers to the distance from the centre of the lens to the principal foci.

Whats the focal length of a lens?

The focal length of a lens is the distance from the principal foci to the center of the lens.

What will happen to the focal length of a lens if it is cut into half vertically?

When the lens is cut vertically then the focal length of the lens will increase.the focal length will become approx double.

Which lens has a greater power convex lens of focal length 10 cm or a convex lens of focal length 20cm?

Power is inversely related to the focal length. So convex lens of focal length 20 cm has less power compared to that having focal length 10 cm

When does lens convexity increase?

when the degree of convergence of a convex lens placed in air increases, we say its convexity has increased. as the power of a lens is the measure of degree of its convergence or divergence, we can increase the convexity of a lens increasing its power this is further achieved by decreasing its focal length. as focal length is inversly proportional to the refractive index of lens we have to decrease in order to increase…

How does the thickness of a lens affect the focal length of a lens?

More the thickness, less the focal length.

Does the focal lens length have three classifications?

yes, focal lens length has three classifications

If a telescope has an objective lens of 3 inches what is the focal length?

The size (diameter) of a lens does not determine its focal length. The amount of curvature of the lens does. Citing a diameter for a lens doesn't help us find the focal length. Lenses are ground to specifications that allow short or long focal length. The more curved the lens, the shorter the focal length. You can see this if we specify a given curvature and then start to "flatten" the lens. The focal length…

What is defined as the distance between a lens and its focal point?

focal length of the lens

What is the focal length of a convex lens?

The distance from the centre of the lens to the focal point.

Explain how the focal length of a convex lens changes as the sides of the lens become less curved?

The focal length of a lens is the distance from the center of the lens to the point at which it focuses light rays. The bigger the focal length, the more powerful the lens. ChaCha!

Does the focal length of a spherical mirror or lens change when placed under water?

i do not think so because a mirror an a lens is two same things except that mirrors can reflect the water and the lens may refract or bend the water so that can change the focal length between the mirror and the lens

Which lens in a refracting telescope has a shorter focal length?

The eyepiece will have a shorter focal length than the objective lens has.

How does change in the thickness of lens change the focal length of lens?

Not at all. The focal length is determined by the curvature of the surfaces.

Will the focal length of a lens change when put in water?

A careful reading of the question raises the uncomfortable suspicion that it might be very difficult to put the focal length in water. However, it's quite possible to put the lens itself in water. When that's done, it's quite likely that the lens's focal length has changed. The refractive indexes of both materials ... the substance of which the lens is made and the medium around it ... are both involved in determining its focal…

How does thickness of convex lens affect focal length?

The thicker the lens is, the shorter the focal length will be, and the bigger the image produced will be.

What is the focal length formulae?

For a lens ... 1/image distance + 1/object distance = 1/focal length of the lens

Difference between focal point and focal length?

The focal point is the point where light converges after it passes through a concave lens. The focal length is the distance of the focal point to the lens. Same for a convex lens, except that the focal point is the imaginary point from where light deflected from lens seems to have emerged.

How can you calculate the focal length of a lens?

Basically, the focal length is the distance from the center of the lens to the focal point or the principal foci. The calculations will depend on the curvature of the lens, the lens thickness, and the refractive index of the material that the lens was made out of. Wikipedia has a great description of lens focal length, see the link to this article in the related link section below.

Will focal length of a convex lens change when immersed in water?

yes. By lens formula the relative refractive index will change. hence the focal lenght increases.

Will the focal lengths of concave and convex lens change in water?

No. Because the medium remains the same and hence the lens' or mirrors' focal length doesnt change

Why does the focal length of a mirror not depend on the mirror material when the focal length of a lens does depend on the lens material?

The focal length for a mirror is determined by the law of reflection from the mirror surface. This law is not governed by the material that the mirror is made by. This means that the focal length depends only on the radius and curvature. Conversely, the focal length of a lens depends on the indices of refraction of the lens meterial and the surrounding medium.

What is a tele conversion lens?

A tele-conversion lens attaches to a digital camera to increase the lens magnification. It enhances the telephoto effect and adds focal length.

Do near objects have a longer focal length?

Focal length is related to the lens.  It has nothing to do with how near or far the object is to the lens or objective.

How does the eyepiece affect the total magnifacation in a telescope?

A telescope consists of two lenses. 1) The main lens which collects the light ( it is relatively bigger that eyepiece). 2) Eye piece , through which we see. Magnification of a telescope depends on the focal length of the eye piece and the main lens. Magnification = Focal length of the main lens / Focal length of the eyepiece . For example : If the focal length of the main lens is 12 units…

How does the eye lens change when you look at a distant object?

As an object gets farther from your eye, the focal length of the lens has to increase. The muscles around the lens stretch it so it has a less convex shape. But when you focus on a nearby object, these muscles make the lens more curved, causing the focal length to decrease.

What is the distance from a lens to one of its foci called?

The distance from the center of a lens to one of its focal points is the focal length of the lens.

How does the thickness of a lens effect its focal length?

For convergent lenses identical in every other respect, the thicker lens will have a shorter focal length.

What is the meaning of focal length in a camera lens?

The focal length of a camera's lens refers to the the magnification or telephoto power of the lens and is expressed in the millimeters of the lens, like 100mm, 300mm, etc. www.goldprints.com

How do you calculate total magnification?

Divide the focal length of the objective lens by the focal length of the eyepiece.

Explain how the focal length changes as a convex lens becomes flatter?

Focal length increases

The distance from lens to focal point is called?

It is called the focal length.

What factors can affect the focal length of a lens?

There are many factors affecting the focal length of a lens, these include: - The thickness of a lens. - The curviture of a lens. - The material the lens is made out of. E.g. Glass or plastic. - The light intensity going through the lens. - The shape of the lens. These, are just few of the many factors that may affect the focal length of a particular lens. I hope this has helped.

What is the difference between a zoom lens and a fixed lens?

A zoom lens you can go from one focal length to another such as 70-200mm and a fixed is one focal length such as 50mm

Why does the lens on a camera have a short focal length?

The short focal length of a camera lens is so that the image the lens forms is small and can be focused on a piece of light-sensitive film.

What is the function of ciliary muscles in Human Eye?

The eye lens is kept in place by ciliary muscles. These muscles can contract or relax.If the ciliary muscles contract or relax the focal length of the eye lens becomes large or small. Or in other words the function of the eye lens is to increase or decrease the focal length of the eye lens.

What is the relation of focal length of eye with its curvature?

More the curvature of the eye lens, lesser the focal length is. Lesser the curvature, greater the focal length is

What will be the power of convex lens having a focal length is 50 cm?

Convert the focal length to meters, then take the reciprocal. That is how the "power" of a lens is calculated.

A concave lens is kept in contact with convex lens of focal length 20cm the combination works as a converging lens of focal length 100cmcalculate the power of concave lens?

i think it is -0.06m i.e. 6cm

What is the Local length of the lens?

i think you mean FOCAL LENGTH.

How can you find focal length of a lens?

It should be written on the lens in 'mm'

Will the focal length of concave lens change in water?

no, because this happens only in the cases of lenses

What is the distance between a lens and its focal point is called?

This is called focal length.

Will focal length of a concave mirror change when placed in water?

Excellent question. The answer is actually yes! According to the lens makers formula, it will change based on the refractive index of the material of the concave mirror wrt the medium. Google Lens makers formula for better understanding! NO! the focal length of the mirror will not change if it would be a lens then the focal length would change. The lens maker's formula is for Lenses only!

Does the thickness of a convex lens affect if you increase the diameter of same focal length?

The focal length of a lens depends on 1. The refractive index of the material 2. Radii of the curvature of the two faces. The lens maker's formula is 1/f = (mu --1) (1/R1 --1/R2) mu- the refractive index of the material with which lens is made R1 and R2 are the radii of curvature of the faces. f- the focal length of the lens thus formed. your question needs clear information. As the thickness…

How can you tell what the focal length is for a lens?

Easy way: Use it to form an image of the sun or moon, and measure the distance of the image behind the lens. When the object is at infinity, the distance between the lens and the image is the focal length of the lens.

What is focal length of a door peephole's lens and is it concave or convex?

The lens in a door peephole is a convex lens with a very short focal length, giving it a wide field of view. If it were on a camera, it would be called a "Fisheye lens".