Question 256: Waves Optics

Question

In a single slit diffraction pattern, identify the incorrect statement from the following.

Accepted Answer

We are dealing with a
single slit diffraction pattern
(Fraunhofer diffraction of a single slit).
Key facts:
In
single slit diffraction
, we do not really get "fringes" like in interference; instead we get a
central maximum
and successive secondary maxima with decreasing intensity on either side.
The
central maximum
is the widest (twice the width of the others). The subsequent secondary maxima are narrower, and their intensities decrease.
Therefore:
Widths of maxima are
not equal
(central maximum is twice as wide as others).
Intensities are
not equal
(the central maximum is brightest, others are weaker).
Hence maxima have
unequal widths and unequal intensities
.
Check options:
A. The fringes have unequal width.
Ã¢ÂÂ Correct (central maximum is wider).
B. The fringes have unequal intensity.
Ã¢ÂÂ Correct (central is brightest).
C. The fringes have unequal width and unequal intensity.
Ã¢ÂÂ Correct (both vary).
D. The fringes have equal width and equal intensity.
Ã¢ÂÂ Incorrect.
Ã¢ÂÂ
Answer: Option D is incorrect.

Answer

The fringes have unequal width.

Answer

The fringes have unequal intensity.

Answer

The fringes have unequal width and unequal intensity.

Answer

The fringes have equal width and equal intensity.

Waves Optics

In a single slit diffraction pattern, identify the incorrect statement from the following.

Choose the correct answer: