1
KCET 2018
MCQ (Single Correct Answer)
+1
-0
A plane wavefront of wavelength $\lambda$ is incident on a single slit of width $a$. The angular width of principal maximum is
A
$\frac{\lambda}{a}$
B
$\frac{2 \lambda}{a}$
C
$\frac{a}{\lambda}$
D
$\frac{a}{2 \lambda}$
2
KCET 2018
MCQ (Single Correct Answer)
+1
-0
In a Fraunhofer diffraction at a single slit, if yellow light illuminating that slit is replaced by blue light, then diffraction bands
A
remain unchanged
B
become wider
C
disappear
D
become narrower
3
KCET 2018
MCQ (Single Correct Answer)
+1
-0
In Young's double slit experiment, two wavelengths $\lambda_1=780 \mathrm{~nm}$ and $\lambda_2=520 \mathrm{~nm}$ are used to obtain interference fringes. If the $n^{\mathrm{th}}$ bright band due to $\lambda_1$ coincides with $(n+1)^{\text {th }}$ bright band due to $\lambda_2$, then the value of $n$ is
A
4
B
3
C
2
D
6
4
KCET 2018
MCQ (Single Correct Answer)
+1
-0
In Young's double slit experiment, slits are separated by 2 mm and the screen is placed at a distance of 1.2 m from the slits. Light consisting of two wavelengths $$6500\mathop A\limits^o $$ and $$5200\mathop A\limits^o $$ are used to obtain interference fringes. Then, the separation between the fourth bright fringes of two different patterns produced by the two wavelengths is
A
0.312 mm
B
0.123 mm
C
0.213 mm
D
0.412 mm
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