 |
| Numerical 02 |
|
| 02. Two wires A and B have the same length of 44 cm, and carry a current of 10 A each. Wire A is bent into a circle and wire B is bent into a square. (a) Which wire produces a greater magnetic field at the centre? (b) Obtain the magnitudes of the fields at the centres of the two wires. |
| |
| Suggested solution: |
| |
| The magnetic field at the centre of a circular coil is |
| |
 |
| |
 |
| |
 |
| |
| Let us now consider the case of wire B which has been bent into a square as shown in the figure. |
| |
 |
| |
| The magnetic field at C (centre of square PQRS) due to current carrying conductor PQ is given by |
| |
 |
| |
| Magnetic field at the centre of the square is given by |
| |
 |
| |
 |
| |
| Clearly, |
| |
 |
| |
 |
| |
| B2 is clearly greater than B1. |
| |
| (b) |
| |
 |
| |
 |
| |
