Coherent light of frequency 6.30 times 10^14 Hz passes through two thin slits an

Question

Coherent light of frequency 6.30 times 10^14 Hz passes through two thin slits and falls on a screen 75.0 cm away. You observe that the third bright fringe occurs at plusminus 3.06 cm on either side of the central bright fringe. (a) How far apart are the two slits? (b) At what distance from the central bright fringe will the third dark fringe occur? Consider two antennas separated by 24.0 m that radiate in phase at 100 MHz. A receiver placed 150 m from both antennas measures an intensity I_0. The receiver is moved so that it is 1.7 m closer to one antenna than the other. (a) What is the phase difference p between the two radio waves produced by this path difference? (b) In terms of Io, what is the intensity measured by the receiver at its new position?

Explanation / Answer

for minima in two slit

d*sintheta = (m+1/2) * lambda

m = 2

d = 0.035 mm = 0.035 x 10^-3 m

tan theta = y/D

theta is small so tan tan theta = sin theta

d*y/D = (m+1/2)*lambda

lambda = c/f = 4.76 x 10^-7 m

D = 75 cm =0.75 m

y = (2+1/2) * lambda * D/d

y = 0.0255 m = 2.55 cm

part 2 )

I = Io*cos^2(phi/2)

phi = 3.56 rad

I = 0.043Io

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---