Light of wavelength \(\lambda\) falls perpendicularly onto a single slit of width \(d\). A diffraction maximum is formed at \(P\) on a faraway screen placed parallel to plane of the slit. The first diffraction minimum is formed at \(Q,\) as shown on the screen. Let \(C\) be a 'point' so that it divides the slit \(AB\) in the ratio \(\dfrac{AC}{CB}=\dfrac12,\) i.e. \(AC\) represents the upper \(\dfrac13^{rd}\) of the slit. The total amplitude of the oscillation arriving from \(AC\) at \(Q\) is \(A_1\) and from \(CB\) at \(Q\) is \(A_2\).
Then:

1. \(2 A_{1}=A_{2}\)
2. \(A_{1}=2 A_{2}\)
3. \(\sqrt{2} A_{1}=A_{2}\)
4. \(A_{1}=A_{2}\)
Subtopic:  Diffraction |
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Electrons (mass \(m\)) moving with a velocity \(v\) are incident normally onto a single slit of width \(d,\) and are detected on a screen placed at a distance \(D\) behind the slit. The central point on the screen where most of the electrons are detected is \(O.\) The closest point to \(O\) where no electrons are detected is \(X.\) Then \(OX\) equals:
1. \(\dfrac{hD}{mvd}\) 2. \(\dfrac{hD}{2mvd}\)
3. \(\dfrac{2hD}{mvd}\) 4. \(\dfrac{3hD}{2mvd}\)
Subtopic:  Diffraction |
 62%
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The width of the central maximum of the diffraction pattern of a single slit of width \(1\) mm equals the width of the slit itself, when the screen is \(1\) m away from it. The wavelength of light used equals:
1. \(250\) nm  2. \(500\) nm 
3. \(1000\) nm  4. \(2000\) nm
Subtopic:  Diffraction |
 68%
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A parallel beam of light of wavelength \(\lambda\) is incident normally on a single slit of width \(d,\) and a pattern of maxima and minima are observed on a screen placed far behind the slit. The first minimum (nearest to the central maximum) is formed at an angle \(\theta,\) where \(\sin\theta=\)
1. \(\dfrac{\lambda}{d}\) 2. \(\dfrac{\lambda}{2d}\)
3. \(\dfrac{2\lambda}{d}\) 4. \(\dfrac{\lambda}{4d}\)
Subtopic:  Diffraction |
 67%
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A parallel beam of light of wavelength \(\lambda=400~\text{nm}\) falls normally onto a single slit of width \(d=0.2~\text{mm},\) placed in front of a screen which is \(50~\text{cm}\) away. The first maximum, next to the central maximum, is formed on the screen at a distance of:
1. \(0.5~\text{mm}\) 2. \(1~\text{mm}\)
3. \(1.5~\text{mm}\) 4. \(2~\text{mm}\)
Subtopic:  Diffraction |
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