Compound Lenses Thin Lenses in Contact

Bookmark added to your notes.
View Notes
×

Equivalent Focal Length of Two Lens in Contact

The tracing ray is the technique of determining or we can say following or the tracing the paths that rays of  light take. It travels in very straight lines that can act like a ray. We can say that the  ray is simply a straight line that originates at a point.  Its wave characteristics are simply not pronounced in such situations. 


The wavelength of light science we can say is less than a micron or a thousandth of a millimeter. It really acts like a ray which is in the many common situations in which it can encounter larger objects than a micron that is such as lenses.


Compound Lenses Explained

For passing rays through matter, the refraction law is used to trace the paths. Here we can use the ray which is tracing to help us understand the lenses of action in situations ranging from forming images on film to magnifying small print to correcting nearsightedness. While the ray which is tracing for complicated lenses, for example such as those found in cameras of sophisticated, which may even require technologies of  computers. 


There are only very few sets of simple rules which are for tracing the rays through lenses which are even thin. A lens of this thin is defined to be one whose whole thickness really allows rays to refract. And as this is illustrated in many otherways. But the whole thing really does not allow us the properties such as dispersion and aberrations.


Focal Length of Two Lenses

A lens which is a simple system which consists of the use of only one lens which is one lens as opposed to the system of compound lens where multiple lenses can be used with a single axis common. The simplest of all those lenses which was compound lens systems are two thin lenses which kept in contact with each other. Let’s study about the lenses which are compound lenses and properties of them.


When the distance which is between the two lenses that is d is equal to the sum of the focal length individual (f1 + f2) the combined length or we can say focal length is infinite. This makes the light ray refracted which is parallel to each other.


The lenses which are used in many things are combined in such a way that two wavelengths are typically the ends violet and red are brought into focus. This is one of the applications which is of using a system of compound lens, where the aberrations of chromatic which can be found using single lenses are corrected.


Learn about optical rays with our expert faculty here at vedantu, the learning app, who would be more than happy to help you start falling in love with the process of learning.


Compound Lenses 

The lens which is Simple are subject to the optical aberrations discussed many times above. In many cases these different aberrations can be compensated for to a great extent which is by using a combination of lenses which are simple with complementary aberrations. 


The case of the simplest is where lenses are placed in contact: that is if the lenses of focal lengths that is  f1 and another one is f2 are which is thin the combined focal length that is f of the lenses is given below:

1/f = 1/f1 + 1/f2


If the distance which is between the separation is equal to the sum of the focal lengths that is d = f1 + f2 the FFL and BFL are infinite. This pair corresponds  to lenses that transform a parallel that is a collimated beam into a collimated another beam. This type of system is known as or called an afocal system, since it produces no net convergence or no net divergence of the beam. The two focal lenses at this separation form the simplest type of telescope which is optical. That is although the system which does not alter the divergence of a collimated beam it does alter the beam width. The telescope magnification is given below:

M = -f2/f1

 

Properties of Lens 

A transmissive lens is an optical device that focuses or we can say that disperses a beam of light by means of refraction. A lens which is simple consists of a single piece of transparent material while a compound lens consists of several lenses which are  simple or elements that usually are arranged along a common axis. The Lenses are made up of materials such as plastic or glass and are ground and polished or molded to a shape desired. 


A lens can focus the light to form an image which is unlike a prism, or we can say which refracts light without focusing. The devices that are similarly focused or waves disperse and radiation other than light visible are also called lenses, such as we can say the lense of microwave, lense of electron, the lense of acoustic, or lense which is explosive.


Most of the lenses are lense which are spherical and there are two surfaces that are parts of the spheres of surfaces. Surface which is of Each can be convex the bulging outwards from the lens, that is the concave that is depressed into the lens or we can say the planar flat.

 

Axis of Lens

The line which is joining the centres of the spheres which is making up the lens surfaces is known as or called the axis of the lens. Typically the lens and their axis passes through the physical centre of the lens, that is because of the way they were manufactured. The Lenses which may be ground or cut after manufacturing to give them a different size and shape. The axis of the lens  may then not pass through the center of mass of the lens.

FAQ (Frequently Asked Questions)

Q1. How Long Does It Take for Our Eyes to Adjust to Lense Which are Contact Lenses?

Ans: between the days of 10 to 12


Before we leave our eye care office practitioner's, she or he will give you instructions for use and care of your  contacts which is new. It can take between around 10 to 12 days to fully adjust to one's lenses. Once we begin using the lenses on our own, we watch for these  side effects during the period of adjustment.

Q2. Is it OK to Wear the Lense of Contact or Contact Lenses Everyday?

Ans: Most of the contact lenses should not be worn during night, as it could increase the risk of infection of the eye. The Contacts that meant for daily or one-time use can generally be worn up to hours like 14 to 16 hours with no problem, but even our doctor may recommend a free contact hour or two before bedtime in order to rest to our eyes

Q3. How Long Do it Reusable the Contacts Last?

Ans: The daily wear contact lenses which can be safely disinfected for reuse for 2 weeks or we can say for a month before discarding. The Daily wear lenses or contact lenses are made to be worn during the day only. but can the safety of all this be reused for up to a month or more.

Q4. Name the Side Effects of Contact Which is Wearing Contact Lenses?

Ans: The lense of Wearing contact puts you at a higher risk of several serious conditions which are including eye infections and ulcers corneal. These are the conditions that can develop very quickly and can be very serious. In rare cases these conditions can cause blindness also.