Question

Question 1 (1.5 points) This assignment is set up for sequential assessment. Complete each question and submit the answer before moving on to the next question. Correct answers for each question will be made available once the maximum number of attempts have been made for each submission. Double Slit Interference 1 Double Slit Interference Double Slit Screen Interference y=Ltane y 10 y = 0 L (destructive). L bright fringes: sine m=0, 11, 12,...(constructive) Dark fringes: above central: sin 8 = ( mm=1,2.. The light from a red laser (He-Ne Laser) passes through a double slit separated by d = 0.012 mm, 1mm = 10-3 m. The third bright fringe is formed on the screen at an angle of 9.10° relative to the incident light. The distance between the double slit and the screen is L = 1.9 m. (a) Find the wavelength of the light in nm, 1nm = 10-ºm. Keep 1 decimal place. 633 nm Correct (100.0%) Submit (b) Find the distance between the third bright fringe and the center of the screen (the central bright fringe) on the screen. Keep 3 decimal places. 0.304 m Correct (100.0%) Submit (c) Find the angle of the second dark fringe relative to the incident light . Keep 2 decimal places. Enter a number Submit (5 attempts remaining) Find the distance between the second dark fringe and the center of the screen (the central bright fringe) on the screen. Keep 3 decimal places.

Answer 1

9.10° relative to light 633 X 109 -3 slit seperation, a 0.012 mm. =0.012X10 Distance between double slit and screen, L = 1.9m It is said that thered is at an angle The condition fore d sind=m m= Oredere mo. fore third oredere 0 - 9.10° ci - 3x Sin (9.109) So, N = 3 a) m2 3 d sind 0.012X 10X M 63 3 mm 2 If y is the distance between thered bright fränge 3 and centreal bright fringe then

Ча tan (9.100) the image L 19 c) 4 = 0.304m Expression of are dark fringe, d Line = (x+42 fore second dark freinge me2 (mt) Sino = d 2+1 ) x 633 X10 0.012 x 103 7.580 H If y is the distance between second dank fringe and center of Screen on the screen, then 8 fan (7. 58 - y 109 11 0.253 m La 2

d) fare breight fringes d sind = mi Putting 0 = 90°, A = 633x109 m d- 3 0.012 X 10 mmax - 3 0.012 X 10 x Sin qo° 633x10-9 18.45 = 18 mage New situation : If now distance between thered bright fringe and centure and centere of Sereen is o. 216 m. then Q. 216 tano 1.9 0.216 1.9 0

fore third bright fringe, d Sino a mi mi 3x63 3x10 Sin (6.499) d = 60 Sint -3 = 0.0168.810 d = 0.0168 mm