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Page 1 RAY OPTICS  I 1. Refraction of Light 2. Laws of Refraction 3. Principle of Reversibility of Light 4. Refraction through a Parallel Slab 5. Refraction through a Compound Slab 6. Apparent Depth of a Liquid 7. Total Internal Reflection 8. Refraction at Spherical Surfaces  Introduction 9. Assumptions and Sign Conventions 10.Refraction at Convex and Concave Surfaces 11.Lens Maker’s Formula 12.First and Second Principal Focus 13.Thin Lens Equation (Gaussian Form) 14.Linear Magnification Page 2 RAY OPTICS  I 1. Refraction of Light 2. Laws of Refraction 3. Principle of Reversibility of Light 4. Refraction through a Parallel Slab 5. Refraction through a Compound Slab 6. Apparent Depth of a Liquid 7. Total Internal Reflection 8. Refraction at Spherical Surfaces  Introduction 9. Assumptions and Sign Conventions 10.Refraction at Convex and Concave Surfaces 11.Lens Maker’s Formula 12.First and Second Principal Focus 13.Thin Lens Equation (Gaussian Form) 14.Linear Magnification Refraction of Light: Refraction is the phenomenon of change in the path of light as it travels from one medium to another (when the ray of light is incident obliquely). It can also be defined as the phenomenon of change in speed of light from one medium to another. Rarer Rarer Denser N N r i r i Laws of Refraction: I Law: The incident ray, the normal to the refracting surface at the point of incidence and the refracted ray all lie in the same plane. II Law: For a given pair of media and for light of a given wavelength, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. (Snell’s Law) µ = sin i sin r (The constant µ is called refractive index of the medium, i is the angle of incidence and r is the angle of refraction.) µ Page 3 RAY OPTICS  I 1. Refraction of Light 2. Laws of Refraction 3. Principle of Reversibility of Light 4. Refraction through a Parallel Slab 5. Refraction through a Compound Slab 6. Apparent Depth of a Liquid 7. Total Internal Reflection 8. Refraction at Spherical Surfaces  Introduction 9. Assumptions and Sign Conventions 10.Refraction at Convex and Concave Surfaces 11.Lens Maker’s Formula 12.First and Second Principal Focus 13.Thin Lens Equation (Gaussian Form) 14.Linear Magnification Refraction of Light: Refraction is the phenomenon of change in the path of light as it travels from one medium to another (when the ray of light is incident obliquely). It can also be defined as the phenomenon of change in speed of light from one medium to another. Rarer Rarer Denser N N r i r i Laws of Refraction: I Law: The incident ray, the normal to the refracting surface at the point of incidence and the refracted ray all lie in the same plane. II Law: For a given pair of media and for light of a given wavelength, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. (Snell’s Law) µ = sin i sin r (The constant µ is called refractive index of the medium, i is the angle of incidence and r is the angle of refraction.) µ TIPS: 1. µ of optically rarer medium is lower and that of a denser medium is higher. 2. µ of denser medium w.r.t. rarer medium is more than 1 and that of rarer medium w.r.t. denser medium is less than 1. (µ air = µ vacuum = 1) 3. In refraction, the velocity and wavelength of light change. 4. In refraction, the frequency and phase of light do not change. 5. a µ m = c a / c m and a µ m = ? a / ? m Principle of Reversibility of Light: Rarer (a) N r i Denser (b) sin i a µ b = sin r sin r b µ a = sin i a µ b x b µ a = 1 or a µ b = 1 / b µ a If a ray of light, after suffering any number of reflections and/or refractions has its path reversed at any stage, it travels back to the source along the same path in the opposite direction. A natural consequence of the principle of reversibility is that the image and object positions can be interchanged. These positions are called conjugate positions. µ Page 4 RAY OPTICS  I 1. Refraction of Light 2. Laws of Refraction 3. Principle of Reversibility of Light 4. Refraction through a Parallel Slab 5. Refraction through a Compound Slab 6. Apparent Depth of a Liquid 7. Total Internal Reflection 8. Refraction at Spherical Surfaces  Introduction 9. Assumptions and Sign Conventions 10.Refraction at Convex and Concave Surfaces 11.Lens Maker’s Formula 12.First and Second Principal Focus 13.Thin Lens Equation (Gaussian Form) 14.Linear Magnification Refraction of Light: Refraction is the phenomenon of change in the path of light as it travels from one medium to another (when the ray of light is incident obliquely). It can also be defined as the phenomenon of change in speed of light from one medium to another. Rarer Rarer Denser N N r i r i Laws of Refraction: I Law: The incident ray, the normal to the refracting surface at the point of incidence and the refracted ray all lie in the same plane. II Law: For a given pair of media and for light of a given wavelength, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. (Snell’s Law) µ = sin i sin r (The constant µ is called refractive index of the medium, i is the angle of incidence and r is the angle of refraction.) µ TIPS: 1. µ of optically rarer medium is lower and that of a denser medium is higher. 2. µ of denser medium w.r.t. rarer medium is more than 1 and that of rarer medium w.r.t. denser medium is less than 1. (µ air = µ vacuum = 1) 3. In refraction, the velocity and wavelength of light change. 4. In refraction, the frequency and phase of light do not change. 5. a µ m = c a / c m and a µ m = ? a / ? m Principle of Reversibility of Light: Rarer (a) N r i Denser (b) sin i a µ b = sin r sin r b µ a = sin i a µ b x b µ a = 1 or a µ b = 1 / b µ a If a ray of light, after suffering any number of reflections and/or refractions has its path reversed at any stage, it travels back to the source along the same path in the opposite direction. A natural consequence of the principle of reversibility is that the image and object positions can be interchanged. These positions are called conjugate positions. µ Refraction through a Parallel Slab: Rarer (a) Rarer (a) Denser (b) N N r 1 i 1 i 2 r 2 M t d y sin i 1 a µ b = sin r 1 sin i 2 b µ a = sin r 2 But a µ b x b µ a = 1 sin i 1 sin r 1 sin i 2 sin r 2 x = 1 It implies that i 1 = r 2 and i 2 = r 1 since i 1 ? r 1 and i 2 ? r 2 . Lateral Shift: t sin d y = cos r 1 t sin(i 1  r 1 ) y = cos r 1 or Special Case: If i 1 is very small, then r 1 is also very small. i.e. sin(i 1 – r 1 ) = i 1 – r 1 and cos r 1 = 1 y = t (i 1 – r 1 ) or y = t i 1 (1 – 1 / a µ b ) µ Page 5 RAY OPTICS  I 1. Refraction of Light 2. Laws of Refraction 3. Principle of Reversibility of Light 4. Refraction through a Parallel Slab 5. Refraction through a Compound Slab 6. Apparent Depth of a Liquid 7. Total Internal Reflection 8. Refraction at Spherical Surfaces  Introduction 9. Assumptions and Sign Conventions 10.Refraction at Convex and Concave Surfaces 11.Lens Maker’s Formula 12.First and Second Principal Focus 13.Thin Lens Equation (Gaussian Form) 14.Linear Magnification Refraction of Light: Refraction is the phenomenon of change in the path of light as it travels from one medium to another (when the ray of light is incident obliquely). It can also be defined as the phenomenon of change in speed of light from one medium to another. Rarer Rarer Denser N N r i r i Laws of Refraction: I Law: The incident ray, the normal to the refracting surface at the point of incidence and the refracted ray all lie in the same plane. II Law: For a given pair of media and for light of a given wavelength, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. (Snell’s Law) µ = sin i sin r (The constant µ is called refractive index of the medium, i is the angle of incidence and r is the angle of refraction.) µ TIPS: 1. µ of optically rarer medium is lower and that of a denser medium is higher. 2. µ of denser medium w.r.t. rarer medium is more than 1 and that of rarer medium w.r.t. denser medium is less than 1. (µ air = µ vacuum = 1) 3. In refraction, the velocity and wavelength of light change. 4. In refraction, the frequency and phase of light do not change. 5. a µ m = c a / c m and a µ m = ? a / ? m Principle of Reversibility of Light: Rarer (a) N r i Denser (b) sin i a µ b = sin r sin r b µ a = sin i a µ b x b µ a = 1 or a µ b = 1 / b µ a If a ray of light, after suffering any number of reflections and/or refractions has its path reversed at any stage, it travels back to the source along the same path in the opposite direction. A natural consequence of the principle of reversibility is that the image and object positions can be interchanged. These positions are called conjugate positions. µ Refraction through a Parallel Slab: Rarer (a) Rarer (a) Denser (b) N N r 1 i 1 i 2 r 2 M t d y sin i 1 a µ b = sin r 1 sin i 2 b µ a = sin r 2 But a µ b x b µ a = 1 sin i 1 sin r 1 sin i 2 sin r 2 x = 1 It implies that i 1 = r 2 and i 2 = r 1 since i 1 ? r 1 and i 2 ? r 2 . Lateral Shift: t sin d y = cos r 1 t sin(i 1  r 1 ) y = cos r 1 or Special Case: If i 1 is very small, then r 1 is also very small. i.e. sin(i 1 – r 1 ) = i 1 – r 1 and cos r 1 = 1 y = t (i 1 – r 1 ) or y = t i 1 (1 – 1 / a µ b ) µ Refraction through a Compound Slab: Rarer (a) Rarer (a) Denser (b) N N µ b r 1 i 1 r 1 r 2 r 2 i 1 Denser (c) µ c N sin i 1 a µ b = sin r 1 sin r 1 b µ c = sin r 2 a µ b x b µ c x c µ a = 1 sin r 2 c µ a = sin i 1 a µ b x b µ c = a µ c or b µ c = a µ c / a µ b or µ a µ c > µ bRead More
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