Why does a magnetic field form around a conductor when current flows, but not when the current stops? What does this reveal about electricity and magnetism?
رو گزرنے پر موصل کے گرد مقناطیسی میدان کیوں بنتا اور رو رکنے پر کیوں ختم ہوتا ہے؟ اس سے برق و مقناطیس کی نوعیت کے بارے میں کیا معلوم ہوتا ہے؟
Solution & explanation
Moving electric charges produce magnetic effects. With no sustained current, that contribution is absent; this shows electricity and magnetism are linked. Remanent magnetism in nearby magnetic material can remain, so not every field must vanish.
Independent study answer. Original textbook ↗ · English-medium printed page 137.