Electromagnetism » Exercise – 1
1. The induced voltage across a coil with 250 turns that is located in a magnetic field that is changing at a rate of 8 Wb/s is ________.
(a) 1,000 V
(b) 2,000 V
(c) 31.25 V
(d) 3,125 V
2. When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage ________.
(c) remains constant
(d) reaches zero
3. For a given wirewound core, an increase in current through the coil ________.
(a) reverses the flux lines
(b) decreases the flux density
(c) increases the flux density
(d) causes no change in flux density
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
5. If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density ________.
(c) remains the same