vcaa got it wrong?detail study sound

[allstar]

hey guys there is something suss i found on the vcaa exams
vcaa 2012: q12 ans is C therefore claims that dynamic microphones can operate under electromagnetic induction
vcaa 2013 q7 and is D therefore claims that dynamic microphones cannot operate under electromagnetic induction

can someone please clarify?

thank you

[atom]

Dynamic loudspeakers do not operate on induction unlike dynamic microphones, velocity microphones also work using induction, so that's the correct answer

[allstar]

so vcaa 2012 was wrong?

[atom]

No, because dynamic microphones work under the principles induction, so both 2012 and 2013 papers are right. If you read the question in the 2013 paper, the answer for D states dynamic loudspeaker, not dynamic microphone.

[allstar]

whats the difference in operation between the two microphone version doesuse electromagnetic induction, but loudspeaker doesn't?

[atom]

Dynamic loudspeakers are based on induced magnetic fields, unlike dynamic and velocity microphones which are based on electromagnetic induction.