Wave Optics - Physics PYQ & Practice Test

In Young’s double slit experiment, the separation between the slits is halved and the distance between the screen is doubled. The fringe width is

In a diffraction pattern due to a single slit of width \(a\), the first minimum is observed at an angle \(30 \Upsilon\) when light of wavelength \(500 \mathrm{~nm}\) is incident on the slit. The first secondary maximum is observed at an angle of

The wavefront is a surface in which

The position of the direct image obtained at O, when a monochromatic beam of light is passed through a plane transmission grating at normal incidence is shown in figure. The diffracted images A, B, and C correspond to the first, second and third order diffraction. When the source is replaced by another source of shorter wavelength,

When monochromatic light of wavelength 600 nm is used in Young's double slit experiment, the fifth order bright fringe is formed at 6 mm from the central bright fringe on the screen. If the experiment is conducted with light of wavelength 400 nm from the central bright fringe, the third order bright fringe will be located at

Young's double slit experiment is conducted with monochromatic light of wavelength 5000\(\mathop A\limits^o\), with slit separation of 3 mm and observer at 20 cm away from the slits. If a 1 mm transparent plate is placed infront of one of the slits, the fringes shift by 6 mm . The refractive index of the transparent plate is

In Young's double slit experiment the slits are 3 mm apart and are illuminated by light of two wavelengths \(3750 \mathop A\limits^o\) and \(7500 \mathop A\limits^o\). The screen is placed at 4 m from the slits. The minimum distance from the common central bright fringe on the screen at which the bright fringe of one interference pattern due to one wavelength coincide with the bright fringe of the other is

If a slit of width $x$ was illuminated by red light having wavelength $6500\mathop {\rm{A}}\limits^{\rm{^\circ }}$, the first minima was obtained at $\theta=30^{\circ}$. Then, the value of $x$ is

In Young's double slit experiment, the wavelengths of red and blue lights used are $7.5 \times 10^{-5} \mathrm{~cm}$ and $5 \times 10^{-5} \mathrm{~cm}$ respectively. If $n$th bright fringe of red color coincides with $(n+1)$ th bright fringe of blue colour, then the value of ' $n$ ' is

In Young's double slit experiment, the wavelength of monochromatic light is increased by $20 \%$ and the distance between the two slits is decreased by $25 \%$. If the initial fringe width is 0.3 mm , then the final fringe width is

An unpolarised beam of light incidents on a group of three polarising sheets arranged such that the angle between the axes of any two adjascent sheets is $30^{\circ}$. The ratio of the intensities of polarised light emerging from the second and third sheets is

In Young's double slit experiment, if the distance between the slits is increased to 3 times initial distance, then the ratio of initial and final fringe widths is