Explanation Questions Flashcards
Magnetic Fields
Explain why hall probes are usually made using a semiconductor material rather than a metal.
Semiconductors have smaller number density of charge carriers.
Hall voltage (Vh) is inversely proportional to the number density of charge carriers (n).
Hence, hall voltage (Vh) is larger, making it easier to detect.
Magnetic Fields
Explain why, a metal ring suspended from a fixed point, oscillates less when placed near poles of a magnet than when it’s alone.
Similar Question: Explain why oscillations of magnet are damped
As the ring moves between the poles, the ring cuts magnetic flux and causes an induced e.m.f. in the ring.
The induced e.m.f. causes induced currents in ring.
Induced current in ring causes a magnetic field around the ring.
The two fields interact to cause a resistive force, and hence fewer oscillations produced.
Medical Physics
Explain why an aluminum filter may be placed in the X-ray beam when producing an X-ray image of a patient.
