What will be the angular width of central maxima in Fraunhofer diffraction when the light of wavelength \(6000~\mathring {A}\) is used and slit width is \(12\times 10^{-5}~\text{cm}\)$$?
1. \(2~\text{rad}\)
2. \(3~\text{rad}\)
3. \(1~\text{rad}\)
4. \(8~\text{rad}\)

A diffraction pattern is observed using a beam of red light. What will happen if the red light is replaced by the blue light?

A parallel beam of monochromatic light of wavelength \(5000~\mathring{A}\) is incident normally on a single narrow slit of width \(0.001\) mm. The light is focused by a convex lens on a screen placed on the focal plane. The first minimum will be formed for the angle of diffraction equal to:
1. \(0^{\circ}\)
2. \(15^{\circ}\)
3. \(30^{\circ}\)
4. \(60^{\circ}\)

The first diffraction minima due to a single slit diffraction is at \(\theta = 30^{\circ}\) for a light of wavelength  \(5000~\mathring {A}.\)  The width of the slit is:
1. \(5\times 10^{-5}~\text{cm}\)
2. \(10\times 10^{-5}~\text{cm}\)
3. \(2.5\times 10^{-5}~\text{cm}\)
4. \(1.25\times 10^{-5}~\text{cm}\)

Red light is generally used to observe diffraction patterns from a single slit. If the blue light is used instead of red light, then the diffraction pattern:

The direction of the first secondary maximum in the Fraunhofer diffraction pattern at a single slit is given by:
\((a\) is the width of the slit) 
1. \(a\sin\theta = \frac{\lambda}{2}\)
2. \(a\cos\theta = \frac{3\lambda}{2}\)
3. \(a\sin\theta = \lambda\)
4. \(a\sin\theta = \frac{3\lambda}{2}\)

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?

A linear aperture whose width is \(0.02\) cm is placed immediately in front of a lens of focal length \(60\) cm. The aperture is illuminated normally by a parallel beam of wavelength \(5\times 10^{-5}\) cm. The distance of the first dark band of the diffraction pattern from the center of the screen is:
1. \(0.10~\text{cm}\)
2. \(0.25~\text{cm}\)
3. \(0.20~\text{cm}\)
4. \(0.15~\text{cm}\)