Tutorial Sheet 1 (Physical Optics) PDF

Course Name: Physics for Engineers Course Code: BPHS 0100 Tutorial Sheet 1 (Physical Optics) 1. If in an interference pattern, the ratio between maximum and minimum intensities is 36:1, find the ratio between the amplitude and...

Course Name: Physics for Engineers Course Code: BPHS 0100 Tutorial Sheet 1 (Physical Optics) 1. If in an interference pattern, the ratio between maximum and minimum intensities is 36:1, find the ratio between the amplitude and intensities of the two interfering waves. [7:5, 49:25] 2. Two coherent sources of intensity ratio 9:1 interfere. Prove that in the interference pattern, (Imax- Imin ) / (Imax + Imin) = 3/5 3. White light is incident normally on a glass plate (in air) of thickness 500 nm and refractive index of 1.5. What is the wavelength (in nm) in the visible region (400 nm- 700 nm) that is strongly reflected by the plate? [600 nm] 4. White light reflected from a soap film (refractive index = 1.5) has a maximum at 600 nm and a minima at 450 nm with no minimum in between. Find the thickness of the film. [3 × 10-7m] 5. In Newton’s rings experiment the diameter of 4th and 12th dark rings are 0.400 cm and 0.700 cm respectively. Deduce the diameter of 20th dark ring. [0.906 cm] 6. If in a Newton’s rings experiment, the air in the interspace is replaced by a liquid of refractive index 1.33, in what proportion would the diameters of the rings change? [0.867] 7. Light containing two wavelengths λ1 and λ2 falls normally onaPlanoconvex lensof radius of curvature R resting on a plane glass plate. If nth dark ring due to λ1 coincides with (n+1)th dark ring due to λ2 then prove that the radius of nth dark ring of 1 2 R wavelength λ1 is (1   2 ) 8. Light of wavelength 5500 Å falls normally on a slit of width 22x 10-5 cm.Calculate the angular position of the second and third minima on either side of the central maximum. [30o, 48.6 o] 9. A 10 cm long tube containing 48 cm3 of sugar solution rotates the plane of polarisation by 5.5˚. If the specific rotation of sugar is 66˚, calculate the mass of sugar in solution. [4 gm] 10. A sugar solution in a tube of length 40 cm produces optical rotation of 16˚. The solution is then diluted to one-third of its previous concentration. Find the optical rotation produced by 60 cm long tube containing the dilute solution. [8˚]