Recent content by Pifagor

I tried that already, with voltage 240V and current 0,514A. That gives me a positive R_L = 30 Ohm, but that answer is still not right. Why is it wrong to calculate the impedance with my equation, without the resistor, over only the LC-circuit (which of course contains the R_L, too, so it is...

Thanks, but I still don't understand. In the above equation, used over the inductor and capacitor, I meant for the R to be the resistance in the inductor. How can an R not increase the impedance? Even if we do it by complex numbers, resistance is always real, right?

Homework Statement We have a resistor of 350 Ohm, an inductor of 0.15H and a capacitor of 10 microfarad, connected in series to an AC source of voltage 240 V and frequency 50 Hz. The measured effective voltage over the resistor is 180V, and over the system of the both the inductor and the...

Thanks!

Homework Statement When solving, say, the double delta function potential well, we fix constants using continuity. If the potential is symmetrical about the origin, can we conclude that the wave function, i.e. the solution, will also be symmetric? I found this way made the calculations much...

.../four letter word /... now it should be OK

Homework Statement I'm trying to understand a proof of the LC-KD identity involving determinants (see attachment), from the book Introduction to Tensor Calculus and Continuum Mechanics by Herinbockel. What is the author saying in the last line of text? How can we sum the deltas in the upper...

Intuitively, I can see the limit evaluates to \frac{2}{3} as x \rightarrow 1, but I don't quite see how I can algebraically justify turning those different roots in the numerator and denominator into a \frac{1}{1}. The thing is, you now have a continuous function in both parts, so the quotient...

Hi, are you familiar with l'Hôpital's rule? In this case, you can derive both the enumerator and the denominator, and then take the limit. If this was new to you, check it out on Wikipedia, for example, it's neat! Regards, Pifagor

Homework Statement Find the pressure on a uniformly charged spherical conducting shell of Radius R and total charge Q. The answer is (Q^2) / (32*π*ε*R^4) I´m fine doing this using the derivative of the energy as the sphere grows to get the force. My question is: Why do I get twice the answer...