4. When the current through the coil of an electromagnet reverses, the ________.
(a) direction of the magnetic field reverses (b) direction of the magnetic field remains unchanged (c) magnetic field expands (d) magnetic field collapses
Answer
Answer : (a)
Explanation
Explanation : No answer description available for this question. Let us discuss.
5555555555 5. If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density ________. (a) increases (b) decreases (c) remains the same (d) doubles
5555555555 11. The induced voltage across a stationary conductor in a stationary magnetic field is ________. (a) zero (b) reversed in polarity (c) increased (d) decreased
5555555555 24. The direction of a magnetic field within a magnet is ________. (a) from south to north (b) from north to south (c) back to front (d) front to back
555555555522. What is the magnetomotive force in a 75-turn coil of wire when there are 4 A of current through it? (a) 18.75 At (b) 30 At (c) 300 At (d) 187 At