Page 2 - 10-phy-12 Geometrical Optics

12. geometrical Optics eLearn.Punjab

After studying this unit, students will be able to:
• Describe the terms used in reflection including normal, angle of incidence, angle of reflection

and state laws of reflection.
• Solve problems of image location by spherical mirrors by using mirror formula.
• Define the terminology for the angle of incidence i and angle of refraction r and describe the

passage of light through parallel-sided transparent material.
• Solve problems by using the equation sin i /sin r = n (refractive index).
• State the conditions for total internal reflection.
• Describe the passage of light through a glass prism.
• Describe how total internal reflection is used in light propagation through optical fibres.
• Describe how light is refracted through lenses.
• Define power of a lens and its unit.
• Solve problems of image location by lenses using lens formula.
• Define the terms resolving power and magnifying power.
• Draw ray diagram of simple microscope and mention its magnifying power.
• Draw ray diagram of compound microscope and mention its magnifying power.
• Draw ray diagram of a telescope and mention its magnifying power.
• Draw ray diagrams to show the formation of images in the normal eye, a short-sighted eye and

a long-sighted eye.
• Describe the correction of short-sight and long-sight.
Science, Technology and Society Connections
The students will be able to:
• Describe the use of spherical mirrors for safe driving, blind turns on hilly roads and dentist

mirror.
• Describe the use of optical fibres in telecommunications and medical field and state the

advantages of their use.
• Describe the use of a single lens as a magnifying glass and in a camera, projector and photographic

enlarger and draw ray diagrams to show how each forms an image.
• Describe the use of lenses/contact lenses for rectifying vision defects of the human eye.
• Describe the exploration of the world of micro-organisms by using microscopes and of distant

celestial bodies by telescopes.

Light is the main focus of this unit. We shall describe different phenomena of light such as reflection,
refraction and total internal reflection. We will learn how images are formed by mirrors and lenses
and will discuss working principle of compound microscope and telescope.

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