Two straight and narrow parallel slits 3 mm apart illuminated by a monochromatic light r-p of wavelength 5.9× 10-7m. Fringes are obtained on a screen 30 cm away from the slits. The fringe width will be :

Question

Two straight and narrow parallel slits 3 mm apart illuminated by a monochromatic light r-p of wavelength 5.9× 10-7m. Fringes are obtained on a screen 30 cm away from the slits. The fringe width will be : (A)  5.9× 10-5m  (B)  2.99× 10-5m  (C)  3.9× 10-5m  (D) none of these

Tardigrade Admin · Accepted Answer

Using the relation, ω =(Dλ /d) Here, d=3mm=3× 10-3m D=30cm=0.30m λ =5.9× 10-7m or ω =(0.30× 5.9× 10-7/3× 10-3)=5.9× 10-5m

Q. Two straight and narrow parallel slits $3 mm$ apart illuminated by a monochromatic light r-p of wavelength $5.9 \times 10^{- 7} m .$ Fringes are obtained on a screen $30 c m$ away from the slits. The fringe width will be :

$5.9 \times 10^{- 5} m$

$2.99 \times 10^{- 5} m$

$3.9 \times 10^{- 5} m$

none of these

Using the relation, $ω = \frac{D λ}{d}$
Here, $d = 3 mm = 3 \times 10^{- 3} m$
$D = 30 c m = 0.30 m$
$λ = 5.9 \times 10^{- 7} m$
or $ω = \frac{0.30 \times 5.9 \times 10 ^{- 7}}{3 \times 10 ^{- 3}} = 5.9 \times 10^{- 5} m$

Q. Two straight and narrow parallel slits 3mm apart illuminated by a monochromatic light r-p of wavelength 5.9×10−7m. Fringes are obtained on a screen 30cm away from the slits. The fringe width will be :

5.9×10−5m

2.99×10−5m

3.9×10−5m