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How do I use this physics equation?

ε = BANω sinωt
Do you use sin or cos because I've seen both
Radians or degrees?
Also if you could answer Q22 on MCQ I would be grateful
https://filestore.aqa.org.uk/sample-papers-and-mark-schemes/2017/june/AQA-74082-QP-JUN17.PDF
Reply 1
Avatar for Teenie2
Teenie2
11
I'm pretty sure you would normally use sin - what is in your textbooks?

Radians - remember that ω is in radians per second.

(22) When the coil is parallel to the field, the emf is at its maximum. i.e. sinωt = 1 . See how you get on from here.
Reply 2
Avatar for Sinnoh
Sinnoh
22
ϵ=BANωsin⁡(ωt) \epsilon = BAN \omega \sin(\omega t) is derived from the fact that ϵ=−NΔϕΔt\epsilon = -N \dfrac{\Delta \phi}{\Delta t}.
If you differentiate BANcos⁡(ωt)BAN \cos(\omega t) with respect to t, you get the above formula - since Faraday's law is that the emf induced is proportional to the rate of change of flux linkage.

Whether you use sin or cos depends on where the starting angle is. Generally what matters is the difference in angle and not necessarily the sine or cosine value itself.
Also remember that ωt is in itself an angle, because angular speed is given in rads-1.

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