Describe briefly how a diffraction pattern is obtained on a screen due to a single narrow slit illuminated by a monochromatic source of light. Hence obtain the conditions for the angular width of secondary maxima and secondary minima.
Answers
Step-by-step explanation:
A single narrow slit is illuminated by a monochromatic source of light. The diffraction pattern is obtained on the screen placed in front of the slits. There is a central bright region called as central maximum. All the waves reaching this region are in phase hence the intensity is maximum.
Answer:
The phenomenon of bending of light round the sharp corners of an obstacle spreading into the regions of geometrical shadow is called diffraction.
Step-by-step explanation:
Expression For Fringe Width : Consider a parallel beam of light from a lens failing on a slit AB. As diffraction occurs, the pattern is focused on the screen XY with the help of lens L2. We will obtain a diffraction pattern that is a central maximum at the centre O flanked by a number of dark and bright fringes called secondary maxima and minima.
Central Maximum : '' Each point on the plane wave front AB sends out secondary wavelets in all directions. The waves from points equidistant from the centre C lying on the upper and lower half reach point O with zero path diffference and hence, reinforce each other, producing maximum intensity at point O.
Positions and Widths of Secondary Maxima and Minima : Consider a point P on the screen at which wavelets travelling in a direction making angle theta with CO are brought to focus by the lens. The wavelets from points A and B will have a path difference equal to BN.
From the right angled `Delta ANB`, we have:
