Mutual Inductance and wire coils

[edlin]

Hi..I am new here and I am really thankful for any help that I may get

I am stuck in a problem of mutual inductance. It seems fairly simple, yet I cannot get the correct answer.

Two coils are close to each other. The first coil carries a time-varying current given by I(t) = (4.60 A) e-0.0250tsin(377 t). At t = 0.800 s, the voltage measured across the second coil is -3.60 V. What is the mutual inductance of the coils?


So, the equation I have used is: emf2 = -M dI1/dt ...which is the voltage of the second coil equals the mutual inductance times the current with respect to time. I solved for M, but the answer is not right.

My answer was: 80 V*s/A and I got various other answers but they are incorrect.

I really, really would appreciate any help! Thankyou so much!

 

[OlderDan]

Hi..I am new here and I am really thankful for any help that I may get

I am stuck in a problem of mutual inductance. It seems fairly simple, yet I cannot get the correct answer.

Two coils are close to each other. The first coil carries a time-varying current given by I(t) = (4.60 A) e-0.0250tsin(377 t). At t = 0.800 s, the voltage measured across the second coil is -3.60 V. What is the mutual inductance of the coils?


So, the equation I have used is: emf2 = -M dI1/dt ...which is the voltage of the second coil equals the mutual inductance times the current with respect to time. I solved for M, but the answer is not right.

My answer was: 80 V*s/A and I got various other answers but they are incorrect.

I really, really would appreciate any help! Thankyou so much!

Is it by any chance more like 472 V*s/A?.

 

[edlin]

Well, I actually did get answers in the hundreds, but when I put my answer in, it tells me it has the wrong magnitude. And since they provide me with the units, it says mHz...so the answer is multiplied by 1/10^3... and I really don't understand why. I get no answer near that.

 

[OlderDan]

Well, I actually did get answers in the hundreds, but when I put my answer in, it tells me it has the wrong magnitude. And since they provide me with the units, it says mHz...so the answer is multiplied by 1/10^3... and I really don't understand why. I get no answer near that.

Are you sure it is mHz and not just mH? The units of inductance are named after Joseph Henry.

H = V·s/A