• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Focal length of Concave and Convex lens

Extracts from this document...

Introduction

          Focal length of Concave and Convex lens

Objective

In this experiment, we are going to use three different methods and one method to find the focal length of an unknown-focal length of convex lens and concave lens.

Apparatus

2 meter rules, a light box, a white-coloured screen, a D.C. power supply, 2 lens holders, a plane mirror, a transparent object F, two-unknown focal length of convex and concave lens.

Theory

Since the convex and concave lenses are made of glasses, the focal lengths are actually the convergent point of all refracted light sources. So, the main theory that we are applying is the refraction theory and also the Lensmaker's equation.

is an equation which shows the relationship between the focal length with the object and image distances. With mathematical simplification, the Lensmaker's equation can be applied as follow image00.png.

Procedure

Type A is a convex lens with shorter diameter

...read more.

Middle

First, put a light source with a transparent object F in front of a convex lens.

Then adjust the distance between the lens and the light source and mark down the distance as D when you can form a sharp image on the screen allocated right beside the light source. The length D is the focal length

METHOD IIIimage04.png

image05.png

By putting the light source in front of the lens and then adjust the distance between the lens and light source and the lens and the screen. Obtain a sharp image and mark down the distance of U and V.

Then plot a graph with U and V to find out the focal length of the lens by applying the equationimage00.png.

Concave lensimage06.png

image07.png

Place the light source in front of the convex lens which is placed between the concave lens and the light source.

...read more.

Conclusion

Actually, whenever we test the focal length of the lenses we need to consider the degree of the curve of the lens. Since some light rays may refracted near the edge of the lenses and the refracted ray may thus get another focal length and thus resulting a unclear image.

On the other hand the nodal inside the lenses is another interesting topic that students should know. Although we cannot apply the knowledge of it in this experiment, I think most of us should know more about it. It is because this is another factor that affecting the degree of refraction of light rays in lenses.

Lastly, since light ray consist of 7different colours,and what we need to know that the distortion of the rays may happen. So we need to make the total distance of the experiment much smaller.

...read more.

This student written piece of work is one of many that can be found in our GCSE Waves section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Waves essays

  1. Deviation of Light by a Prism.

    As you can see from the graph of the Angle of Deviance plotted against the angle of incidence, it is a parabola that achieves a minimum value of 38� when the angle of incidence is 49�. The graph is shaped like it is because, there are in fact two Incident

  2. The aim of my experiment is to see what factors affect electromagnetism the most ...

    To explain this I will say that the constant will have to be above 0 so that others values within the formula will also be above 0 to give a correct answer. But when a value of the number of coils that is above 0 but gives 0 grams of paperclips (which is possible if you look at the graph)

  1. Is there any rule governing the angle light is refracted through?

    I will repeat the experiment three times to get a mean, this also enables me to get more accurate and reliable results. Safety: This experiment is safe. Although the light bulb contained in the ray box may become hot to the touch.

  2. Sideways Displacement of a Light Ray

    But firstly, it is important to get the idea of what does each of terms mean: * A ray is the path taken by light energy. * The construction line drawn at right angles to the glass at the point of incidence is called the normal.

  1. Investigating the factors which affect the sideways displacement of a light ray through a ...

    To find out what r is. I know that the refractive index of glass is 1.52 from a preliminary experiment: Sin i (angle of incidence) =n (refractive index) Sin r (angle of refraction) Sin 30 = 1.52 (what I got from preliminary experiment)

  2. SIGNAL ANALYSIS

    State any precautions, which may be necessary when connecting the two stages together. Document all results and explain all the terms commonly used in connection with filters e.g. dB points, roll off rate expressed in dBs, Corner/cut off frequency, time constant etc... Provide suitable comments where necessary. Part 2: 1.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work