Register to reply

Amplitude of the induced voltage across the coil

by lee.perrin@gm
Tags: induced voltage, inductance, magnetic field
Share this thread:
lee.perrin@gm
#1
Mar30-10, 10:02 PM
P: 8
If anyone can advise that would be great.

1. The plane of a 5 turn coil of 5mm cross sectional area is rotating a 1200 r.p.m in a magnetic field of 10mT.

Q. Calculate the amplitude of the induced voltage across the coil

Data:

5 turns
c = 1200 rpm
A = 5cm
B = 10 mT

2. φ = N.B.A φ = 51010^-3 5 10^-2
φ = 2.5 10^-3

V = dφ/dt or N.A. dB/dt

The equation thought to have been used is the following but the Length is not vissible to me.

V/L = c x B c being the speed
B field
L lenth of wire

3. I have tried two avenues please advise

a: V(t) = -Nd(BA)/dt = -NBdA/dt = NBωAsin(ωt)
V(t) =(5)(10x10^-3)(125.66370599999999)(5)sin(ωt) = 31.415 sin(ωt) volts.

Or

b: And using the following, saying t = 60 sec

Then φ = N.B.A φ = 51010^-3 5 10^-2
φ = 2.5 10^-3

And V = dφ/dt or N.A. dB/dt = 4.17x10^-3 V

My concern here is that 1200rpm was not used.
Phys.Org News Partner Science news on Phys.org
NASA team lays plans to observe new worlds
IHEP in China has ambitions for Higgs factory
Spinach could lead to alternative energy more powerful than Popeye
berkeman
#2
Apr2-10, 05:28 PM
Mentor
berkeman's Avatar
P: 40,649
Quote Quote by lee.perrin@gm View Post
If anyone can advise that would be great.

1. The plane of a 5 turn coil of 5mm cross sectional area is rotating a 1200 r.p.m in a magnetic field of 10mT.

Q. Calculate the amplitude of the induced voltage across the coil

Data:

5 turns
c = 1200 rpm
A = 5cm
B = 10 mT

2. φ = N.B.A φ = 51010^-3 5 10^-2
φ = 2.5 10^-3

V = dφ/dt or N.A. dB/dt

The equation thought to have been used is the following but the Length is not vissible to me.

V/L = c x B c being the speed
B field
L lenth of wire

3. I have tried two avenues please advise

a: V(t) = -Nd(BA)/dt = -NBdA/dt = NBωAsin(ωt)
V(t) =(5)(10x10^-3)(125.66370599999999)(5)sin(ωt) = 31.415 sin(ωt) volts.

Or

b: And using the following, saying t = 60 sec

Then φ = N.B.A φ = 51010^-3 5 10^-2
φ = 2.5 10^-3

And V = dφ/dt or N.A. dB/dt = 4.17x10^-3 V

My concern here is that 1200rpm was not used.
You should write out the function φ(t) (hint: it is a sinusoidal function), then differentiate it to find V(t)...


Register to reply

Related Discussions
Calculate voltage induced on a coil Electrical Engineering 2
Induced EMF on a primary coil by a secondary coil Introductory Physics Homework 1
Solving for Magnetic Field Strength given Induced voltage in a coil Introductory Physics Homework 1
A coil with turns given magnetic field, time find the emf induced in the coil Introductory Physics Homework 4
Induced Voltage in a coil Introductory Physics Homework 2