Question

Rite my concept of Induced Emf is not that clear and i m stuck with these question , any help mite be very useful :)
A long this solenoid has 900 turns/m and radius 2.5 cm.The current in the solenoid is increasing at a uniform rate of 60A/s.What is the magnitude of induced electric field at a point at a distance -.5 cm from axis of solenoid
I know that El = s dB/dt
but i m not sure wheather i shud take l as =-0.5 or 2pi(-0.5) ?WOOP WOOP SOLVED! ,

Answer 1

@ganeshie8 Mind helping? 0:)

Answer 2

I need some help ! urgently

Answer 3

I think you need to use that formula

Answer 4

but what is L?

Answer 5

\[muNi/2a\]

Answer 6

0.5 or 2 pi (0.5) ??

Answer 7

Why do you need to use L?

Answer 8

i need to find induced emf, which which cud be found using El = A dB/dt formula

Answer 9

do we have another formula for it as well? o.O

Answer 10

Yeah!
just give me a moment

Answer 11

I'm not too sure... Are you sure it's the magnitude of the induced ELECTRIC field that you need to find?

Answer 12

yeah

Answer 13

L = \[\mu(n)^2V\]

Answer 14

thats the magnetic field, B

Answer 15

V=Sl is the volume of the solenoid

Answer 16

ohh i c

Answer 17

No... that's the formula for the inductance of a solenoid

Answer 18

S is the cross-sectional area of the solenoid

Answer 19

no actually l here is not the INDUCTANCE , its some length

Answer 20

And l is the length of the solenoid
n=(N/l) is the number of turns per unit length

Answer 21

the concept of induced electric field is that, line integral of E = change in flux

Answer 22

l is the length, I just told you :)

Answer 23

N is the number of turns.

Answer 24

ah i got it

Answer 25

so it wud be El = sdB/dt

Answer 26

so l is length of solenoid?

Answer 27

Yeah! l is the length of the solenoid

Answer 28

0.5?

Answer 29

The point they're considering is inside the solenoid.. because it's -0.5

Answer 30

yea

Answer 31

actually in the equation the things we know are S, N/l , di/dt

Answer 32

i m cofused of l , that is not the length of the solenoid i guess, its the distance from the axis of solenoid at the point where electric field is asked,

Answer 33

i m confused if it shud be 2pi(l) or just l

Answer 34

Probably 2pi l because they haven't mentioned the length right?
Just the radius

Answer 35

they have asked us to find it at a distance of 0.5 , so it i shud put it as 0.5 or 2pi(0.5) ?

Answer 36

Try both and tell me what you come up with.. It's got to be one or the other..

Answer 37

aha dude , using 2pi(o.5) gave the right answer, to naive of me to not try and match values with answer , Thanx :)

Answer 38

No problem :) Best of luck! :)