# For a parallel beam of monochromatic light of wavelength $$\lambda$$, diffraction is produced by a single slit whose width $$a$$ is much greater than the wavelength of the light. If $$D$$ is the distance of the screen from the slit, the width of the central maxima will be: 1. $$\frac{2D\lambda}{a}$$ 2. $$\frac{D\lambda}{a}$$ 3. $$\frac{Da}{\lambda}$$ 4. $$\frac{2Da}{\lambda}$$

Subtopic:  Diffraction |
82%
From NCERT
NEET - 2015
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In a double-slit experiment, the two slits are $$1~\text{mm}$$ apart and the screen is placed $$1~\text{m}$$ away. Monochromatic light of wavelength $$500~\text{nm}$$ is used. What will be the width of each slit for obtaining ten maxima of double-slit within the central maxima of a single-slit pattern?
1. $$0.2~\text{mm}$$
2. $$0.1~\text{mm}$$
3. $$0.5~\text{mm}$$
4. $$0.02~\text{mm}$$
Subtopic:  Young's Double Slit Experiment |
52%
From NCERT
NEET - 2015
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A beam of light of $$\lambda = 600~\text{nm}$$ from a distant source falls on a single slit $$1~\text{mm}$$ wide and the resulting diffraction pattern is observed on a screen $$2~\text{m}$$ away. The distance between the first dark fringes on either side of the central bright fringe is:
1. $$1.2~\text{cm}$$
2. $$1.2~\text{mm}$$
3. $$2.4~\text{cm}$$
4. $$2.4~\text{mm}$$

Subtopic:  Diffraction |
63%
From NCERT
AIPMT - 2014
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In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is $$\lambda$$ is $$K$$, ($$\lambda$$ being the wavelength of light used). The intensity at a point where the path difference is $$\frac{\lambda}{4}$$ will be:
1. $$K$$
2. $$\frac{K}{4}$$
3. $$\frac{K}{2}$$
4. zero

Subtopic:  Young's Double Slit Experiment |
64%
From NCERT
AIPMT - 2014
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In Young’s double slit experiment, the slits are $$2~\text{mm}$$ apart and are illuminated by photons of two wavelengths $$\lambda_1 = 12000~\mathring{A}$$ and $$\lambda_2 = 10000~\mathring{A}$$. At what minimum distance from the common central bright fringe on the screen, $$2~\text{m}$$ from the slit, will a bright fringe from one interference pattern coincide with a bright fringe from the other?
1. $$6~\text{mm}$$
2. $$4~\text{mm}$$
3. $$3~\text{mm}$$
4. $$8~\text{mm}$$

Subtopic:  Young's Double Slit Experiment |
67%
From NCERT
AIPMT - 2013
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A parallel beam of fast-moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statements is correct?
 1 The angular width of the central maximum of the diffraction pattern will increase. 2 The angular width of the central maximum will decrease. 3 The angular width of the central maximum will be unaffected. 4 A diffraction pattern is not observed on the screen in the case of electrons.
Subtopic:  Diffraction |
51%
From NCERT
AIPMT - 2013
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Two periodic waves of intensities I1 and I2 pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is:

1.  $2\left({\mathrm{l}}_{1}+{\mathrm{l}}_{2}\right)$

2.  ${\left({\sqrt{\mathrm{I}}}_{1}+{\sqrt{\mathrm{l}}}_{2}\right)}^{2}$

3.  ${\left({\sqrt{\mathrm{I}}}_{1}-{\sqrt{\mathrm{l}}}_{2}\right)}^{2}$

4.  $2\left({\sqrt{\mathrm{I}}}_{1}-{\sqrt{\mathrm{l}}}_{2}\right)$

Subtopic:  Superposition Principle |
74%
From NCERT
AIPMT - 2008
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At the first minimum adjacent to the central maximum of a single slit diffraction pattern, the phase difference between the Huygen’s wavelet from the edge of the slit and the wavelet from the midpoint of the slit is:
1. $$\frac{\pi}{4}\text{radian}$$
2. $$\frac{\pi}{2}\text{radian}$$
3. $${\pi}~\text{radian}$$
4. $$\frac{\pi}{8}\text{radian}$$

Subtopic:  Diffraction |
59%
From NCERT
NEET - 2015
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Two slits in Young’s experiment have widths in the ratio of $$1:25$$. The ratio of intensity at the maxima and minima in the interference pattern $$\frac{I_{max}}{I_{min}}$$ is:
1. $$\frac{9}{4}$$
2. $$\frac{121}{49}$$
3. $$\frac{49}{121}$$
4. $$\frac{4}{9}$$

Subtopic:  Young's Double Slit Experiment |
75%
From NCERT
NEET - 2015
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In Young's-double slit experiment, the distance between the slits and the screen is doubled. The separation between the slits is reduced to half. As a result the fringe width:
 1 is halved 2 become four times 3 remains unchanged 4 is doubled
Subtopic:  Young's Double Slit Experiment |
79%
From NCERT
NEET - 2013