An a.c. generator consists of a coil of 50 turns and an area 2.5 m2 rotating at an angular speed of 60 rad s-1 in a uniform magnetic field of 0.3 T between two fixed pole pieces. What is the flux through the coil, when the current is zero?
Correct answer: A. Maximum
- A. Maximum
- B. Minimum
- C. Zero
- D. To independent of current
Explanation
The current is 0 when the coil is vertical (perpendicular to the magnetic field). At this position the magnetic flux through the coil is maximum because θ=90° and sin90°=1.
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Magnetic flux density and magnetic flux describe the strength of a magnetic field and the field passing through a surface. A charged particle moving through a magnetic field experiences a force perpendicular to its velocity and may follow circular or helical motion, depending on the angle between velocity and field.
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