This ray is refracted along BC and bent towards the normal because it is going from air to glass. And if this is a smaller number, this is a larger number. (ii) Lateral shift is directly proportional to the incident angle. • Remove the glass block, draw in the emergent ray and the refracted ray and measure the angle of refraction, r. • Repeat the experiment for the other angles of incidences, 0 o, 30 o, 45 o and 60 o • Tabulate the values of the angles i and r, and also using the calculator, the values of sin i and sin r. THEORY: • State the laws of refraction. This angle is called the angle of the prism. When a ray of light enters a glass block at an angle other than the normal, it changes speed, wavelength and direction as shown below. The technique is capable of producing a high degree of visual realism, more so than typical scanline rendering methods, but at a greater computational cost. In this experiment, we'll be going to prove: 1. Episode 317-1: Refraction: soldiers walking from tarmac onto sand (Word, 60 KB) Student experiment: Ray tracing through rectangular block. When light passes from air through a block with parallel sides, it emerges parallel to the path of the light ray that entered it. Refraction is the change of direction of light rays as they pass at an angle from one medium to another of different optical densities Explanation: To investigate the path of light through rectangular glass block. Remove the glass block and at a point 0, draw a normal, NON, as shown in figure 2.5. Fig. The figure given here shows the path of a light ray through a rectangular glass (or any refracting material. Your IP: 18.104.22.168 That’s called “dispersion”. 1) You can experiment with refraction using a light source and a _____ rectangular block on top of a piece of _____ 2) Shine a light ray at an _____ into the block, some light reflected, but lots of it is _____ as it passes through the glass. Practical: investigate the refraction of light, using rectangular blocks, semi-circular blocks and triangular prisms In your examination you might be asked to write a method explaining how you could investigate the refraction of light through different shaped blocks. 2. 3. A ray AE is incident on the face PQ at an angle of incidence i. Proof for i = e Case-I: For light going from air to glass at point E. µa sin i = µg sin r ….. (1) Case-II: For light going from glass to air at point F. µg sin r = µa sin e ….. (2) From (1) & (2) we can say that i = e ⇒ incident & emergent rays are parallel to each other. 5. On entering the glass slab, it bends towards normal and travels along EF at an angle of refraction r. There is shift in the path of light on emerging from a refracting medium with parallel faces. Performance & security by Cloudflare, Please complete the security check to access. Diagram A Shows a ray of light passing through glass. Compare Refraction through a rectangular parallel surfaced glass block and Refraction through a glass prism – a ray of light from the air when passes through a rectangular glass block with parallel surfaces then refraction happens twice – (1) when light enters from air to glass and (2) when it comes out of the glass block to the air. If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. A ray of light AB incident at an angle of incidence iwith the normal NN1at the point of incidence B. 6. Place the rectangular glass block on the paper and trace its outline. (i) A ray of light passes from water to air. And we actually see it here. Refraction in a Rectangular Block. This phenomenon is observed when a ray of light gets refracted twice while passing from air to a parallel-sided glass block and then again to air. The refraction of light in glass prism is different from a glass slab. If you take a glass prism, you can see that it has 2 triangular bases and three rectangular lateral surfaces, inclined at an angle. • Set up your apparatus as shown in the diagram using a rectangular block. Assuming the light exits the block along the side opposite to the side it entered, what path does the light follow when it emerges from the block? (iii) Lateral shift is directly proportional to the refractive index of glass slab. • There is a tendency for pupils to associate refraction solely with what happens when light passes through rectangular glass blocks. Factors on which lateral shift depends are: (i) Lateral shift is directly proportional to the thickness of glass slab. So something where light travels really slowly where light travels really slowly, this will be a smaller number. Now, we have seen that before. Join up crosses with a ruler. Cloudflare Ray ID: 600f976ace1a1498 2.5: Investigating the path of light through glass block Procedure Fix the white plain paper on the soft board using drawing pins. In 3D computer graphics, ray tracing is a rendering technique for generating an image by tracing the path of light as pixels in an image plane and simulating the effects of its encounters with virtual objects. On entering the glass slab, it bends towards normal and travels along EF at an angle of refraction r. The refracted ray EF is incident on face SR at an angle of incidence r’. Refraction of Light through a Glass Block. Traced its outline and indicated the centre of the flat side. Don’t worry about diffraction here. Shine the light ray through the glass block. The emerged ray FD bends away from the normal at an angle of refraction e. Thus the emergent ray FD is parallel to the incident rays AE, but it has been laterally displaced with respect to the incident ray. Refraction of light rays at two of the surfaces of a triangular glass or plastic prism. 1. Refraction or deflection is the bending of light as it passes from one transparent substance into another. Refraction of light rays at the two surfaces of a diverging concave lens. Refraction of Light PART I This laboratory was designed to investigate the behaviour of light as it travels through a less dense into a denser medium. When light passes through glass, the light ray refracts, which means it bends towards the middle. THEORY: Consider a rectangular glass slab EFGH as shown in fig. Let’s look at a top view of a triangular prism with a ray of light entering it. BN is normal to interface between air and the refracting block.