Question

When a magnetic needle is placed below a current carrying wire, current moves upward, there is a deflection towards east. but if the needle is placed above the conductor,(direction of current remains same), the deflection is towards west. Why?

Answer 1

According to the question when a current carrying conductor is placed in a plane along north - south direction and the current through the conductor is going towards south and the direction of current is constant.we know that the current creates a magnetic field around the conductor which is circular around the wire , now using the right hand thumb rule we place the right hand thumb in direction of current the we find that in the lower portion of wire the curl fingers is in direction of east and in upper part its curl part is towards west it means that in lower part the magnetic field is towards east , and in upper part magnetic field is in west which ultimately applies the force on needle in same direction and the needle makes turn .