Which one is not produced by sound waves in air?

A point source of monochromatic light is situated at the centre of a circle, what is the phase difference between the light waves passing through the end points of any diameter

An unpolarised light of intensity $32  \mathrm{W} / \mathrm{m}^{2}  $ passes through three polarisers, such that the transmission axis of last polarizer is perpendicular with the first. If the intensity of emergent light is $3  \mathrm{Wh}  $ Im $ ^{2} $ then the angle between the transmission axes of the first two polarisers is:

Two polaroids are oriented with their transmision axes making angle of $30^{\circ}$ with each other. The fraction of indicent unpolarised light is transmitted.

The axes of the polarizer and analyzer are inclined to each other at an angle of $60^{o}$. If the amplitude of polarized light emerging through the analyzer is $A$, the amplitude of unpolarized light incident on the polarizer is

Unpolarised light of intensity $I _{0}$, is passed through a polarizer. What is the intensity of the transmitted light ?

Two polorides are placed having their transmission axis at an angle of $45^0$. If unpolarised light is incident on first polorid acting as polarizer then, calculate intensity of emergent light from second polariser:-

Plane polarized light is passed through a Polaroid. Now the Polaroid is given one complete rotation about the direction of light propagation. When viewed through another Polaroid (analyser), one of the following is observed:

When an unpolarised light is polarized, then the intensity of light of the polarized wave :

Unpolarized light of intensity $I _{0}$ is incident on a polarizer and the emerging light strikes a second polarizing filter with its axis at 45$^{\circ}$ to that of the first. The intensity of the emerging beam :

Two Polaroids $P _1$ and $P _2$ are placed with their axis perpendicular to each other. Unpolarized light $l _0$ is incident on $P _1$. A third polaroid $P _3$ is kept in between $P _1$ and $P _2$ such that its axis makes an angle $45^{\circ}$ with that of $P _1$. The intensity of transmitted light through $P _2$ is 

Three polaroides are placed one above other, such that the first and the last polaroids are crossed with each other. If the angle between the transmission axis of the first two polaroids is $45$, then what is the percentage of incident light transmitted through the combination of three polaroids?

For a given medium, the polarising angle is $60^o$. What will be the critical angle for this medium?

A light has amplitude A and angle between analyzer and polarizer is.$60 ^ { \circ }$ Light is transmitted by analyzer has amplitude. 

The polaroids are placed in the path of unpolarized beam of intensity $I _{0}$ such that no light is emitted from the second polaroid. If a third polaroid whose polarization axis makes an angle $\theta$ with the polarization axis of first polaroid, is placed between these polariods then the intensity of light emerging from the last polaroid will be

A Polaroid examines two adjacent plane polarised beams $A$ and $B$ whose planes of polarisation are mutually perpendicular. In the first position of the analyser, beam $B$ shows zero intensity. From this position a rotation of $30^{o}$ shows that the two beams have same intensity. The ratio of intensities of the two beams $I _{A}$ and $I _{B}$ will be

In, the visible region of the spectrum the rotation of the plane of polarization is given by $\displaystyle\theta=a+\frac{b}{\lambda^2}$. The optical rotation produced by a particular material is found to be $30^0$ per $mm$ at $\lambda=5000A^o$ and $50^0$ per $mm$ at $\lambda=4000A^o$. The value of constant $a$ will be

An unpolarized beam of intensity $2a^2$ passes through a thin Polaroid. Assuming zero absorption in the Polaroid, the intensity of emergent planes polarized light will be  

A beam of unpolarized light is passed first through a tourmaline crystal $A$ and then through another tourmaline crystal $B$ oriented so that its principal plane is parallel to that of $A$. The intensity of final emergent light is $I$. If $A$ is rotated by $45^0$ on a plane, perpendicular to the direction of incident ray, then intensity of emergent light will be

Unpolarized light of intensity $32Wm^{-2}$ passes through three polarizes such that the transmission axis of the last polarizers is crossed with that of the first. The intensity of final emerging light is $3Wm^{-2}$.The intensity of light transmitted by the first polarizered will be 

A beam of unpolarized light is passed first through a tourmaline crystal $A$ and then through another tourmaline crystal $B$ oriented so that its principal plane is parallel to that of $A$. The intensity of final emergent light is $I$. The value of the $I$ is 

A beam of unpolarized light is passed first through a tourmaline crystal $A$ and then through another tourmaline crystal $B$ oriented so that its principal plane is parallel to that of $A$. The intensity of final emergent light is $I$. Flux of energy of the incident ray is $10^{-3}W$, the percentage of incident light transmitted by the second polarizered will be____

A beam of unpolarized light is passed first through a tourmaline crystal $A$ and then through another tourmaline crystal $B$ oriented so that its principal plane is parallel to that of $A$. The intensity of final emergent light is $I$. The intensity of the emergent beam, if flux of energy of the incident ray is $10^{-3}W$, will be (in $W/m^2$)

A Plane polarized light is incidents on an analyzer. The intensity then becomes three-fourth. The angle of the axis of the analyzer with the beam is

An unpolarized beam of light is incidents on a group of four polarizing sheets, which are arranged in such a way, that of the characteristic direction of each polarizing sheet makes an angle of $30^0$ with that of the preceding sheet. The percentage of incident light transmitted by the first polarizered will be :

Intensity observed in an interference pattern is $I={ I } _{ 0 }\sin ^{ 2 }{ \theta  } $. At $\theta={30}^{o}$, intensity $I=5\pm 0.002$. The percentage error in angle if $I _0=20w/m^2$is

When light passing through rotating nicol is observed, no change in intensity is seen. What inference can be drawn ?

Unpolarised light of intensity 32 W m$^{-2}$ passes through three polarizes is crossed with that of the first. The intensity of final emerging light is 3 W m$^{-2}$. The intensity of light transmitted by first polarizer will be

A beam of unpolarised light passes through a tourmaline crystal $A$ and then through another such crystal $B$ oriented so that the principal plane is parallel to $A$. The intensity of emergent light is $\displaystyle I$. If $A$ now rotated by $45^{o}$ in a plane perpendicular to direction of the incident ray. The emergent light will have intensity.

Three or more number of polaroids ($n$) kept in the path of unpolarized light of intensity $I$ such that angle between any two successive polaroids is other than $90^{\circ}$, then the intensity of emergent light is :

Ordinary light passes through two polarizing filters. The filters have been rotated so that their polarizing axes are oriented at $90^{\circ}$ to each other, and no light gets through both of them.
By adding a third polarizing filter so that there are three in a row, how might one cause light to pass through the three filters?

Polarizing filter # $1$ Is oriented so that its polarizing axis is vertical.
Polarizing filter # $2$ is oriented so that its polarizing axis is rotated clockwise $45^{\circ}$ from filter # $1$
Polarizing filter # $3$ is oriented so that its polarizing filter is rotated $90^{\circ}$ from filter #$1$
Polarizing filter # $4$ oriented so that its polarizing is rotated $135^{\circ}$ from filter # $1$
Which sequence of filters-front to back-will block out all light that starts through the front filter?

Unpolarized light falls on two polarizing sheets placed one on top of the other. What must be the angle between the characteristic directions of the sheets if the intensity of the final transmitted light is one-third the maximum intensity of the first transmitted beam

Two circularly shaped linear polarisers are placed coaxially. The transmission axis of the first polarizer is at $30^o$ from the vertical while the second one is at $60^o$, both in the clockwise sense. If an unpolarised beam of light of intensity $I=20$ $W/m^2$ is incident on this pair of polarisers, then the intensities $I _1$ and $I _2$ transmitted by the first and the second polarisers, respectively, will be close to.

A transparent thin plate of a polaroid is placed on another similar plate such that the angle between their axes is $30^\circ$. The intensities of the emergent and the unpolarized incident light will be in the ratio of

Unpolarised light of intensity $32\ W\ m^{-2}$ passes through three polarizers such that transmission axis of first is crossed with third. If intensity of emerging light is $2\ W\ m^{-2}$, what is the angle of transmission axis between the first two polarisers? 

On unpolarised beam of light is incident on a set of four polarising plates, such that each plate makes an angle of $\dfrac{\pi}{3}$ with preceding sheet. The light transmitted through the combination is:-

Two polaroids are kept crossed to each other. Now one of the polaroids is rotated through an angle $45^0$. The percentage of incident light now transmitted through the system is: 

A plane polarized light is incident normally on a tourmaline plate. Its $\vec { E } $ vectors make an angle of ${ 60 }^{ o }$ with the optic axis of the plate. Find the percentage difference between initial and final intensities.