The distance between two parallel horizontal wires carrying the same current in opposite directions

JAMB Physics 2023 56 views

The distance between two parallel horizontal wires carrying the same current in opposite directions is 20 cm. If the force between the wires per unit length is 1 x 10-4 Nm-1, calculate the current carried by the wires. Is the force between the wires attractive or repulsive? [μo = 4π x 10-7 NA-2]

The distance between two parallel horizontal wires carrying the same current in opposite directions is 20 cm. If the force between the wires per unit length is 1 x 10-4 Nm-1, calculate the current carried by the wires. Is the force between the wires attractive or repulsive? [μo = 4π x 10-7 NA-2]

  1. 6 A, Attractive
  2. 10 A, Repulsive ✓
  3. 6 A, Repulsive
  4. 10 A, Attractive

Explanation

A p-n junction forms where p-type and n-type semiconductors meet. At the junction, electrons and holes combine, creating a depletion zone with no mobile charges.

Forward bias (positive to p, negative to n) reduces depletion zone – current flows. Reverse bias increases depletion zone – no current (until breakdown voltage).

Diodes allow current one way only – used in rectifiers (AC to DC). LEDs emit light when forward biased. Solar cells generate voltage when light hits the junction.

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