Lens equation

Inference Image distance depends on object distance.Hypothesis When the distance of object increases, the distance of image also increases.

Aim To find the relationship between the distance of object and distance of image.Variables : Manipulated variable : u

Responding variable : vConstant variable : focal length

Apparatus Convex lens, metre rule, screen, light bulb, power supplyArrangement of the apparatus

method 1. The apparatus is set up as shown in the diagram.2. A ray box is placed ____ cm from the lens3. The screen is moved until a sharp image is obtained. The distance between the lens

and the screen is measured using metre rule.4. The steps above is repeated for u=____cm, ___ cm, _____ cm, and ______ cm.5. Graph 1/v against 1/u is plotted.

Tabulate data

u(cm) v(cm) 1/u (cm-1) 1/v (cm-1)

Conclusion Precaution

Snell’s Law

Inference Angle of refraction depends on angle of incidence increasesHypothesis When the angle of incidence increases, the angle of refraction also increases.

Aim To study the relationship between the angle of incidence and angle of refractionVariables : Manipulated: Angle of incidence, i

Responding: Angle of refraction, rConstant: Refractive index

Apparatus Ray box, glass block, paper, pencil, protractorArrangement of the apparatus

method 1. The outline of the glass block is traced on a sheet of white paper and labeled.2. The glass block is removed. Point O is marked on one side of the glass block. With a protractor, lines forming angles of incidence 20°, 30°, 40°, 50° and

60° are drawn and marked.3. The glass block is replaced on its outline on the paper.4. A ray of light from the ray box is directed along 20° line. The ray emerging on the other side of the block is drawn.5. Step 4 is repeated for the other angles of incidence 20°, 30°, 40°, 50° and 60°.6. The glass slab is removed. The points of incidence and the corresponding points of emergence are joined. The respective angles of refraction are measured with a protractor.7. Graph sin i against sin r is plotted.

Tabulate data

i/o r/o Sin i Sin r

Conclusion Precaution