# Relativistic Transformations of Electric and Magnetic Fields

*Most recent answer: 11/03/2012*

Q:

ok..heres one problem....i am inside a train,,the train is moving..and there is one electron inside a train ..and i am looking at that electron..in my perspective the electron is not moving and (as my high school teacher told) only moving charged particle creates magnetic field...so i will not see any magnetic field..but suppose my friend is looking that electron sitting outside the train..then he will see a magnetic field is created...then here is a problem...what is happenning in reality..is there a magnetic field or not,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,does a independent reality exist??

- aawaz (age 17)

pokhara,kaski,nepal

- aawaz (age 17)

pokhara,kaski,nepal

A:

Your facts are correct: you see only a static electric field whereas your friend sees a combination of electric and magnetic fields. There is no problem because there is a relativistic transformation between the train system and the ground system that mixes up the

See:

for details.

LeeH

Just to address your last question, yes, an independent reality exists in the following sense: certain physical properties are the same regardless of which reference system you use to describe them. These "invariants", however, are not the familiar variables such as

*and***E***fields. Your friend sees both a magnetic field whose value is given by the standard Maxwell equations as well as an electric field .***B**See:

for details.

LeeH

Just to address your last question, yes, an independent reality exists in the following sense: certain physical properties are the same regardless of which reference system you use to describe them. These "invariants", however, are not the familiar variables such as

**E**and**B**but rather combinations of them. Basic physical outcomes (does a particle bump into another one or not) are invariant aspects of that independent reality. /Mike W.*(published on 11/03/2012)*