10B11PH111 Additional
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10B11PH111 (PHYSICS – I, 2012-13) 1. In front of lecture hall, a coherent beam of monochromatic light from a He- Ne laser (=632.8 nm) illuminated a double slit. From there it travels a distance of 20.0m to a mirror at the back of the hall and returns the same distance to the screen: (a) In order that the distance between interference maxima is 10.0 cm, what should be the distance between the slits? (b) State what you will see if the lecturer slips a thin sheet of cellophane over the one of the slits. The path through the cellophane contains 2.5 waves than the path through the air of same geometrical thickness. 2. In a two slit experiment with monochromatic light, fringes are obtained on screen placed at some distance from the slits. If the screen is moved by 5×10 -3 m towards the slits, the change in fringe width is 3×10 -5 m. If the distance between the slits is 10 -3 m, calculate the wavelength of the light used. 3. In a particular two slit interference pattern with =600 nm , the zero order and 10th order maxima fall at micrometer readings 12.34 mm and 14.73 mm. if is changed to 500nm , deduce the positions of the zero and 20 th order fringes, other arrangements remaining the same. 4. A beam of light consisting two wavelengths 650 nm and 520nm is used to obtain interference fringes in Young’s double slit experiment. The distance between the slits is 2.0 mm and the distance between the plane of slits and the screen is 120cm. a. Find the distance of the third bright fringe on the screen from the central maximum for the wavelength 650nm. b. What is the least distance from the central maximum where the bright fringes due to both the wavelengths coincide? 5. A double slit of separation 1.5mm is illuminated by the white light (400nm- 800nm). On a screen 120cm away colored interference pattern is formed. If a pinhole is made on this screen at a distance 0f 3.0 mm from the central white fringe, what wavelengths will be absent in the transmitted light? 6. Interference fringes are produced by Fresnel’s bi-prism in the focal plane of an eye piece 200 cm away from the slit. The two images of the slits are formed for each of the two positions of a convex lens placed between the bi- prism and eye-piece are found to be separated by 4.5mm and 2.9mm respectively. If the width of the interference fringes be 0.326 mm, find the wavelength of light used.
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Transcript of 10B11PH111 Additional
10B11PH111 (PHYSICS – I, 2012-13)
1. In front of lecture hall, a coherent beam of monochromatic light from a He-Ne laser (=632.8 nm) illuminated a double slit. From there it travels a distance of 20.0m to a mirror at the back of the hall and returns the same distance to the screen:
(a) In order that the distance between interference maxima is 10.0 cm, what should be the distance between the slits?
(b) State what you will see if the lecturer slips a thin sheet of cellophane over the one of the slits. The path through the cellophane contains 2.5 waves than the path through the air of same geometrical thickness.
2. In a two slit experiment with monochromatic light, fringes are obtained on screen placed at some distance from the slits. If the screen is moved by 5×10 -3m towards the slits, the change in fringe width is 3×10 -5m. If the distance between the slits is 10-3m, calculate the wavelength of the light used.
3. In a particular two slit interference pattern with =600 nm , the zero order and 10th order maxima fall at micrometer readings 12.34 mm and 14.73 mm. if is changed to 500nm , deduce the positions of the zero and 20th order fringes, other arrangements remaining the same.
4. A beam of light consisting two wavelengths 650 nm and 520nm is used to obtain interference fringes in Young’s double slit experiment. The distance between the slits is 2.0 mm and the distance between the plane of slits and the screen is 120cm.
a. Find the distance of the third bright fringe on the screen from the central maximum for the wavelength 650nm.
b. What is the least distance from the central maximum where the bright fringes due to both the wavelengths coincide?
5. A double slit of separation 1.5mm is illuminated by the white light (400nm-800nm). On a screen 120cm away colored interference pattern is formed. If a pinhole is made on this screen at a distance 0f 3.0 mm from the central white fringe, what wavelengths will be absent in the transmitted light?
6. Interference fringes are produced by Fresnel’s bi-prism in the focal plane of an eye piece 200 cm away from the slit. The two images of the slits are formed for each of the two positions of a convex lens placed between the bi-prism and eye-piece are found to be separated by 4.5mm and 2.9mm respectively. If the width of the interference fringes be 0.326 mm, find the wavelength of light used.
