Lens Definition and 836 Threads

A friend and I are getting conflicting answers for a focal length/power question. He says he gets 22.5 diopters, whereas I get 5.1 diopters, so I was wondering who's screwing up. Here is the question and my answer: Q: If a +20 diopter lens is a symmetric double convex lens of index 1.50...

New 3x Barlow lens and a 2x "shorty" barlow lens I bought a new 3x Barlow lens and a 2x "shorty" barlow lens. I haven't done any stacking yet, but I tried the shorty and the 3x on Thursday night. It was cold and it was a work night, so I set up my telescope on my brightly-lit front porch (its...

If you had to choose between ice(n=1.31), glass (n=1.52), or diamond(n=2.42) which would be the hardest lens to make? Which woukl be the easiest lens to make?? the one with the least radius of curvature would need the most work done on it because of the small value needed. On the other hand...

Hi, Im working on a project in designing a (TOF) mass spectrometer and want to include an einzel lens in order to help focus the ion beam onto the detector. I know the basics behind the operation of the lens, but am struggling to find any equations for the focal length of an einzel lens...

One of our lab assignments was to use a lens to focus an arrow-shaped beam of light onto a sheet of paper. We were then told to predict what would happen if we covered up the top/bottom/left/right half of the lens. I predicted that covering the top portion would cause the bottom part of the...

Hello I've been reading optics (both the cartesian and real/virtual sign convention) and I have some queries: 1. I was trying to work out problems involving silvered lenses (spherical lens with one side silvered) and first I tried to reason to myself how the imaging would take place. This...

The projection lens in a certain slide projector is a single thin lens. A slide 20.0 mm high is to be projected so that its image fills a screen 2.0 m high. The slide-to-screen distance is 3.00 m. (a) Determine the focal length of the projection lens. (b) How far from the slide should the...

A transparent photographic slide is placed in front of a converging lens with a focal length of 2.24 cm. The lens forms an image of the slide 11.4 cm from the slide. (a) How far is the lens from the slide if the image is real? (b) How far is the lens from the slide if the image is virtual...

I got a problem where it gives us a diagram with a lens, a source and a image. We have to draw the three principal rays. But after drawing the rays, how can I tell if it is a diverging or converging len? And how can I explain it verbally? Thanks a lot!

i just want to know, does the lens which present in the eye consider as living or non-living ? please can u provide me with a proper explanation. thenk you

To look at the SDI through a scientific lens, one can formulate a lot of arguments for and against its legitimacy. However, to what extent do you guys believe that Reagan's Strategic Defense Initiative brought about the end of the Cold War?

Hi my teacher assigned a few challenging optics problems, I got most of them but I am stuck on this one.. "Find a position on the principle axis that will ensure |hi| = ho ". When is the height of the image equal to the height of the object? How would I go about solving this?

Rotating microscope lens I have a question regarding spinning clear lens's on microscopes. If you spin a lens at a great velocity will it somehow refract light/electrons that comes up from below allowing for a better image of say any object on a slide for viewing ? In...

Converging lens made of ice Would it be possible to start a fire by shaping a piece of ice ? That's the question. I'm thinking that yes it would be possible if you shaped the ice in the form of a converging lens. Even though the lens is made of ice, the sun rays would not burn through it...

Would it be possible that Opticians will be selling to visually impaired people, Contact Lens, made from a material that has a negative index refraction, that theoretically could be altered with a Liquid Crystal "Eye-Drop" solution? Basically how far are we from a Liquid Crystal Contact Lens...

Hi, I'm first year Engineering in the Phys1130 course at my college and I've ended up hitting a large brick wall with the pre-lab. The pre-lab section of the experiment goes: "The thin lens equation is: (1/do) + (1/di) = (1/f) di = distance from lens to image do = distance from...

What am I missing here? A person looks at a gem using a converging lens with a focal length of 15.0 cm. The lens forms a virtual image 26.0 cm from the lens. Determine the magnification. (1/p)+(1/q) = (1/f) p=? q=26 cm f=15 cm (1/15)-(1/26)= Ans^-1 = 35.5 cm (p) Magnification=...

im in a slight fix. i am presently using a light sensor. i was asked to use a lens along with it recently. is it because the obect i am going to sense is magnified by the lens so that sensor can detect it easily? but, let's take the situation where a real image is formed because of the lens...

im in a slight fix. i am presently using a light sensor. i was asked to use a lens along with it recently. is it because the obect i am going to sense is magnified by the lens so that sensor can detect it easily? but, let's take the situation where a real image is formed because of the lens...

I am having some trouble with this one...any help would be appreciated. A 31.8cm focal length converging lens is 21.6cm behind a diverging lens. Parallell light strikes the diverging lens. After passing through the converging lens, the light is again parallel. What is the focal length of...

A converging lens (convex) and a concave mirror, both of focal length 5.0 cm, are arranged with their axes in line. The lens and the mirror are 10.0 cm apart and a candle is placed 3 cm infront of the mirror. By using a ray diagram or some other metho, find the location of all the images...

how can we find the focus ?thanks

In my physics lab, we have been assigned to find the focal length of a lense that was given to us. The professor says it can be found by using this formula: Object distance over 1 plus 1 over the Image Distance will equal one over the Focal Length. So, we put a piece of white paper at ground...

1) Aconverging lens with a focal length of 7 cm forms an image of a 4 mm tall real object that is to the left of the lens. The image 1.10 cm tall and erect. Where is the object located? Where is the image located? 2) A converging lens with a focal length of 12 cm forms a virtual image 5 mm...

Convex Lens How about this simulation program How about this ?>

Lens Problems problem 24. A person looks at a gem using a concverging lense with a focal length of 13.7 cm. The lense forms a virtual image 35.5 cm from the lense. a) Find the magnifaction. This is what I have done so far: f=13.7 , q= -35.5 1/p+1/q=1/f 1/f-1/q=1/p...

problem 24. A person looks at a gem using a concverging lense with a focal length of 13.7 cm. The lense forms a virtual image 35.5 cm from the lense. a) Find the magnifaction. This is what I have done so far: f=13.7 , q= -35.5 1/p+1/q=1/f 1/f-1/q=1/p...

i need some help with this problem anyone want to give it a shot? thanks A camera is supplied with two interchangeable lenses, whose focal lengths are 35.0 and 150.0 mm. A woman whose height is 1.80 m stands 10.00 m in front of the camera. What is the height (including sign) of her image on...

Anyone know of a place I can go to help me understand lens reflections?

Spy planes fly at extremely high altitudes (24.0 km) to avoid interception. Their cameras are reportedly able to discern features as small as 5.48 cm. What must be the minimum aperture of the camera lens to afford this resolution? (Use lambda = 550 nm.) This problem is unfamiliar to me, I'm...

Can someone get me started on this, I know how to work a diverging lens and a concave mirror, just not together. The problem: A concave mirror with a radius of curvature of 20.0 cm is placed 25.0 cm from a diverging lens with a focal length of 16.7 cm. An object is placed midway between the...

I have two questions that i couldn't do, it aint that hard: 1.An object is placed 30.0cm from a convex lens of f=10.0cm. Find the position and the magnification of an image. (f = focal length) An object is placed 20.0cm from a convex lens of f=30.0cm. Find the position and the magnifying...

Can anyone help me on these 2 questions? 1.An object is placed 30.0cm from a convex lens of f(focal length)=10.0cm. Find the position and the magnification of an image. 2. An object is placed 20.0cm from a convex lens of f=30.0cm. Find the position and the magnifying factor of an image...

My discman has stopped working recently. When I put a CD in and push play, the disc spins for a while and eventually the display reads "No Disc." It occurred to me that maybe my discman isn't recognizing CDs because the lens is smudged, but I'm not sure. Any advice? Should I shell out some money...

Tried this problem for about 2 hrs and no dice... A spy satellite orbiting at 150 km above the Earth's surface has a lens with a focal length of 3.5 m and can resolve objects on the ground as small as 36 cm; it can easily measure the size of an aircraft's air intake. What is the effective...

Compute the focal length in air of a thin biconvex lens (n=1.5) having radii of 20 and 40 cm. Locate and describe the image of an object 40cm from the lens. my answer: 1/f = (n-1)(1/R1-1/R2) 1/f = (1.5-1)(1/20-1/40) 1/f = .5(.025) f = 1/.0125 = 80cm (convering lens because f is...