A coil of 9 turns is in the shape of an ellipse having amajor axis of 23.0 cm an

Question

A coil of 9 turns is in the shape of an ellipse having amajor axis of 23.0 cm and a minor axis of 18.00 cm. The coilrotates at 71rpm in a region in which the Earth's magnetic field is82.0 microT. (a) What is the maximum voltage induced in the coil ifthe axis of rotation of the coil is along its major axis and thisaxis of rotation is aligned perpendicular to the Earth's magneticfield? (b) What is the maximum voltage induced in thecoil if the axis of rotation of the coil is along its major axisand this axis of rotation is aligned parallel to theEarth's magnetic field?

(A=ab, a = length of the semi-major axis, b = lengthof the semi-minor axis. The major axis in an ellipse isthe long axis; the minor is the short axis. Semi meanshalf.)
N = 9
a = 16.5 cm = .165 m
b = 9 cm = .09 m
B = 82.0e-6 T
= -N( B / t)
= Bvl

Do I use the Faraday's Law equation or do I use the motional emfformula? I'm guessing that's where the 71 rpm is supposed to comein? Will rate lifesaver!


A coil of 9 turns is in the shape of an ellipse having amajor axis of 23.0 cm and a minor axis of 18.00 cm. The coilrotates at 71rpm in a region in which the Earth's magnetic field is82.0 microT. (a) What is the maximum voltage induced in the coil ifthe axis of rotation of the coil is along its major axis and thisaxis of rotation is aligned perpendicular to the Earth's magneticfield? (b) What is the maximum voltage induced in thecoil if the axis of rotation of the coil is along its major axisand this axis of rotation is aligned parallel to theEarth's magnetic field?

(A=ab, a = length of the semi-major axis, b = lengthof the semi-minor axis. The major axis in an ellipse isthe long axis; the minor is the short axis. Semi meanshalf.)
N = 9
a = 16.5 cm = .165 m
b = 9 cm = .09 m
B = 82.0e-6 T
= -N( B / t)
= Bvl

Do I use the Faraday's Law equation or do I use the motional emfformula? I'm guessing that's where the 71 rpm is supposed to comein? Will rate lifesaver!

Explanation / Answer

E = - /t        the inducedvoltage by Faraday's Law = N B A     the total flux thru thecoil = 9 * 8.2 * 10E-5 * .23 * .18 = 3.05 * 10E-5 weber (tesla-m2) P (period) = 1 / f = 1 /71 = .0141 min = .845 sec t = P / 4  = .211 sec    flux goes from min to max in 1/4 revolution E = 3.05 * 10E-5 / .211 = 1.44 * 10E-4 V = .144 mV b)   if the axis of the coil is parallel to themagnetic field then no flux passes thru the coil and hence no change of flux thru the coil and there is noinduced Emf

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.