This diagram shows a current-carrying wire frame placed between a pair of Magnadur magnets on a yoke. A pointer is attached to the wire.

A current of 8.5 A in the wire causes the pointer to move vertically upwards. A small paper tape is attached to the pointer and the current is adjusted until the weight of the paper tape causes the pointer to return to its initial position (with no current and no paper tape). The mass of the paper tape is 60 mg. The section of the wire between the poles of the magnetic has a length of 5.2 cm.
a. State the direction of the magnetic field.
b. Calculate the force on the wire due to the magnetic field when it carries a current of 8.5 A.
c. Calculate the magnetic flux density of the magnetic field between the poles of the magnet.
d. Describe what happens to the frame if low-frequency alternating current passes through the wire.

Transcribed Image Text:

pointer 5.2 cm Magnadur magnets on yoke wooden blocks Figure 24.30