that was the only question of the exam that really confused me. my friend who did quanta to quarks said that its in that option topic. i had no idea cos i did age of silicon. but if this is true (could anyone verify?) then this is an extremely unfair question as this would have disadvantaged at least half the candititure. gees and i thought hsc exams were supposed to be fair.....
anyways, i came up wif this explaination, no one seems to have the same one as me, could anyone comment?:
When the electron is travelling close to the speed of light, length contraction must be taken into account. Relative to the electron, the magnetic field appears to distort, contracting in the direction of travel. (put in length contraction formula). For a charge to undergo uniform circular motion within a magnetic field, the magnetic field must be uniform and this contraction causes the field to become un-uniform. Thus to account for this, the magnetic field around the electron must distort to accomodate for this, or more specifically, the magnetic field must be stretched around the electron so that the relative to the electron, the magnetic field is uniform, ensuring that the electron undergoes uniform circular motion.,