HAHAHAHAHAHAHA!!! OMG i know what ive done! .. i used my left hand.. cuz i was friken WRITING with my rightfizzwizz said:Hi The correct answer to this q is B I think.Use Lenz's law to answer it, and we will take answer C to show that it is incorrect.
If current goes through globe from X to Y then a current moves upwards from brush Y to the handle. Now think of this current as a current in a single conductor pointing upwards, passing through the magnetic field which is directed from left to right. Now use the right hand push rule: current up, fingers pointing left to right................this produces a force on the conductor (disc) into the page. But it is already moving into the page (at the bootom) so this force would increase its jmotion, not decrease its motion as required by lenzs law. A force has got to act on the conductor pushing it out of the field, as it enters the field. Using current flow downwards from handle to brush Y gives you this force. So answer is B.
that is incorrect. The answer is CXcarvengerX said:7 is D because you have to use pythagoras to calculate the diagonal length AND also sin 90 NOT sin 45. If you use either pythagoras but sin 45 OR sin 90 but not pythagoras, then you get C which is incorrect.
The bold line is the part where you got it wrong. Look at the diagram again. The conductor is already perpendicular to the magnetic field line, therefore you use sin 90. The 45 degree is to indicate that the conductor is indeed passing through as the diagonal of the square magnetic field.eX-Bhai said:that is incorrect. The answer is C
By using basic trig, Sin 45 = 0.4 / L
Therefore 0.4 = L.sin45
By using the formula F = BILsin@
B = 0.5 T
A = 3 A
Lsin@ = 0.4
Therefore F = 0.6 N