Question

An electron beam is moving south to north just above a magnetic needle, then the magnetic needle will point towards (ignoring earth's magnetic field): A) West C) North east B) East D) South​

Answer 1

Answer:

South I am sure

Hence from right hand thumb rule, the magnetic field above the wire is towards the south, which is the same direction as that of earth's magnetic field. Hence the compass points towards the south.

Answer 2

The correct option to the following question is (D), which is south.

• When an electron beam is moving south to the north above a magnetic needle, then the magnetic needle will point towards the south.
• According to the right-hand thumb rule, the magnetic field will point from north to south above the wire, and so the magnetic needle will point towards the south.

• When an electron is moving south to north, then the direction of current will be opposite to that of the flow of electron, that is from north to south.
• Now apply the right-hand thumb rule, in which the current-carrying wire is held on the right hand. Then the thumb points the current direction and all other fingers surrounding the wire give the magnetic field direction due to the current.
• Therefore, the magnetic field will point towards the south.