This question is incomplete, the complete question is;
A flat coil is in a uniform magnetic field. What angle between the magnetic field and the plane of the coil produces the maximum flux, and what angle produces 90% of the maximum flux
A) max: 0°
90% of max: 90°
B) max: 90°
90% of max: 45°
C) max: 90°
90% of max: 64°
D) max: 0°
90% of max: 26°
E) max: 90°
90% of max: 80°
Answer:
Option C) max: 90°
90% of max: 64° is the correct Answer
Explanation:
from the Suppose Area is A.
then flux at angular position O is
Ф = BAsin∅
⇒ Ф = βmaxSin∅
flux will be max when sin∅ = 1
therefore sin∅ = 1
∅ = sin⁻¹ 1
∅ = 90°
Now at 90% of max flux
Ф ⇒ 0.9βmax = βmax sin∅
0.9 = sin∅
∅ = sin⁻¹ (0.9)
∅ = 64.15° ≈ 64°
Therefore Max ∅ = 90°
90% flux = 64°
Option C) max: 90°
90% of max: 64° is the correct Answer
