Recent content by herich

If the lone pairs of a nitrogen is tied up in aromatic resonance, it cannot be a good base. But, how can I know which nitrogen has its lone pairs resonating in the structure? And what does "inversion of the lone pair" means? Do you refer to the upper nitrogen?

Homework Statement Arrange the nitrogen atoms of histamine in order of their decreasing basic strength. http://img134.imageshack.us/img134/7339/histamine.th.jpg Homework Equations The more ready the nitrogen atoms donate lone pair, the greater the basicity; The Attempt at a Solution The...

Actually there are the figures deduced from my friend's tutor. But I know that first we can treat the network as two parallel networks, and the two sides of the capacitors can simply computed by using the formula Q=VC. I just doubt how <+60>and <-60> can be found out. And how to deduce in what...

I'm sorry, but what's "nodes of interest"?

http://img366.imageshack.us/img366/4260/note0002ku2.th.jpg I don't understand how can I draw a new network finding the equivalent network. Are there any techniques that I have to know? Also, can the technique also applied to capacitor network finding equivalent capacitor network~...

http://img359.imageshack.us/img359/8205/note0001tx2.th.jpg How can I know the top 2 plates are +60 and below are -60? 120+(-60) and 30+(-90)? And how can I fill in the blanks~?

Sorry, "the last question" is the extra question I want to ask for clarifying my concept. So, I've concluded the above discussion as the following: For vertical system: - added at top, equilibrium position lowers and amplitude increases - added at equilibrium position, equilibrium position...

amplitude must decreases And at the extreme point, amplitude will not change? (because at that point, the speed is 0) And the last question, back to the condition when the plasticine is placed on the mass when the mass is in the original equilibrium position(vertical spring-mass). The...

I understand now! But what about when the plasticine is placed on the mass when the mass is in the original equilibrium position? The equilibrium will lower, right? (I think it is because the mass of the system increases) But what about the horizontal system? When the mass increases, period...

Actually, I have the diagram already~ But I don't understand why at the highest position, the equilibrium will be lowered, but not when at the lowest position. Also, how about when the mass is at the original equilibrium position? k=4*pi*pi*m/(T*T), m is changed, and T is not? confused... =.=

A plate of mass m is supported by a light spring fixed vertically on the ground. A plasticine is dropped gently onto the block when it is are the highest position. Which of the following statements is/are correct? 1) The amplitude of the oscillation would increase since the equilibrium position...

There are primary and secondary coils in a transformers. So, what hat are the difference between when the secondary coil is in 1)open circuit, 2)closed circuit with a load, and 3) shorted circuit? When can the ideal transformer equation be used? It seems that not only is it related to whether...

I see. That means however the secondary coil 's area change, B-field only exists along the iron core. So, the "effective" area of the area of the secondary coil is still the same. Thanks!

There is a soft iron bar, with two coils wound at the two end. A current source is connected to the primary coil. A resistor is connected to the secondary coil. So, the question is: "Whether increasing the area of the secondary coil but keeping the area of the primary coil unchanged can...

Is it mean that if the charge is static, then the E-field = 0? And about the electrical field lines, if I draw the diagram, i) for the capacitor, from left to right ii) inside the conductor, from right to left Is it mean that the two lines cancel out each other? Thx