Manav made an electric circuit and placed a magnetic compass near it. What will happen to the magnetic needle when he switches the circuit ' ON '? Justify your answer.

Asked by Shreeya Nemani | 25th Aug, 2018, 02:51: PM

Expert Answer:

- If a magnetic neeedle is placed around the electric circuit, and if the circuit is switched on,the magnetic needle will show a deflection.
- Generally, a magnetic needle, like that of a navigator's compass, points towards the Earth's geographic North.
- But when a current carrying circuit is placed near it, the magnetic fields formed due to the flow of electric current in that circuit will cause the magnetic needle to deflect.
- That is the reason why the deflections will occur in that magnetic needle.
- The direction of magnetic field developed due to the current carrying conductor can be leant with the help of Right hand thumb rule.
Right Hand Thumb Rule:
- Magnetic field lines around the current carrying conductor can be realised using the right hand rule as shown in figure.
- Thumb points the current direction and direction of fingers shows the direction of magnetic field line. 
- Hence in the picture given in the question magnetic compasses placed above and below the current carrying conductor.
- Magentic field directions are opposite at both points with respect to each other. 
 - Hence the needles will deflect in opposite direction

Answered by Abhijeet Mishra | 27th Aug, 2018, 04:07: PM