Two slits spaced 0.420 mm apart are placed a distance of 80.0 cm from a screen.

Question

Two slits spaced 0.420 mm apart are placed a distance of 80.0 cm from a screen.

Part A

What is the distance between the second and third dark lines of the interference pattern on the screen when the slits are illuminated with coherent light with a wavelength of 510 nm ?

Two slits spaced 0.420 mm apart are placed a distance of 80.0 cm from a screen.

Part A

What is the distance between the second and third dark lines of the interference pattern on the screen when the slits are illuminated with coherent light with a wavelength of 510 nm ?

Explanation / Answer

Second dark line occurs when

d*sin(a) = (3/2)L

sin(a) = 3L/(2d) = 3*5.1*10^(-7)/(2*4.20*10^(-4))

a = 0.10436 deg

Third dark line when

d*sin(b) = (5/2)L

sin(b) = 5L/(2d) = 5*5.1*10^(-7)/(2*4.20*10^(-4))

b = 0.1739 deg

Distance from centre of screen to first line = 0.8*tan(0.10436) = 1.456*10^(-3) m

Distance to second line = 0.8*tan(0.1739) = 2.43*10^(-3) m

Difference = 9.74*10^(-4) m

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.