Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: sr1609 on 25/08/2015 20:14:23

Title: what happens to magnetic field vector in polarisation of light ?
Post by: sr1609 on 25/08/2015 20:14:23

the electric and magnetic vectors are orthogonal to each other . if electric vector is in plane of axis of polariser then the magnetic vector is in direction perpendicular to plane of axis of polariser . is the magnetic vector allowed to pass through ?

Title: Re: what happens to magnetic field vector in polarisation of light ?
Post by: Colin2B on 25/08/2015 22:49:13

Yes it is still there. It is an essential component of the light.

Title: Re: what happens to magnetic field vector in polarisation of light ?
Post by: evan_au on 26/08/2015 14:57:15

There are several ways to produce polarization of an unpolarized  light beam.
- Some use conductive molecules or nanocrystals which "short out" the electric field of one polarization. However, light of the perpendicular polarization passes through, with its magnetic component unchanged.
- Other methods use a glass sheet in which reflected light is strongly polarized, while the remaining light continues through. Both beams of light retain their electric field, with the perpendicular magnetic field.

See: https://en.wikipedia.org/wiki/Polarizer

Title: Re: what happens to magnetic field vector in polarisation of light ?
Post by: sr1609 on 27/08/2015 16:55:13

Quote from: Colin2B on 25/08/2015 22:49:13

Yes it is still there. It is an essential component of the light.

  thanks colin , but how does the magnetic vector perpendicular to axis of polariser can pass through , only those components will pass which are parallel to axis of polariser . in that case, wouldn't be electric and magnetic vibrations in same plane .   

Title: Re: what happens to magnetic field vector in polarisation of light ?
Post by: Colin2B on 27/08/2015 18:25:32

Quote from: sr1609 on 27/08/2015 16:55:13

  thanks colin , but how does the magnetic vector perpendicular to axis of polariser can pass through , only those components will pass which are parallel to axis of polariser . in that case, wouldn't be electric and magnetic vibrations in same plane .

Most polarising materials act only on the electric field either blocking or passing both components of the wave. The magnetic part doesn't have to 'pass' because the changing electric field and the changing magnetic field are an integral part of the wave, if you stop one you stop the other.