All Questions
54
questions
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votes
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answers
31
views
Current sensitivity in transformer scheme with SQUID
I've tried to determine the maximum current sensitivity in this transformer scheme but I'm not sure if my solution is valid. I need to find the relation between the current in the input transformer ...
0
votes
1
answer
35
views
What does "90 degrees ahead of phase" mean in inductance problems?
I've been working on this homework problem and I have determined that the induced EMF on the right coil is sin(x-90). However, I do not understand what "ahead of phase means." When I graph ...
- 101
1
vote
2
answers
119
views
How to compute the resistance of a nonuniform cylinder with varying resistivity?
The generally quoted formula foe resistance is
\begin{equation}
R = \rho \ell/A
\end{equation}
some special cases are easy to solve. For example the case where the current flowing along the z-axis and ...
- 196
0
votes
1
answer
34
views
How to find the capacitance between two metal sheets [closed]
Let’s say I have two metal sheets in a 2D plane. The first one has area A, the second one is infinitely long, and they are separated from each other by a distance d. How can I find the capacitance ...
0
votes
0
answers
29
views
Non-standard circuit
I partially solved this problem.
Problem: A charged sphere of radius $a$ is connected through a resistance $R$ to the earth. An electronic flow breaks out towards the sphere of infinity at speed $v$ ...
4
votes
1
answer
63
views
Why In the following $RL$ circuit, the connection to $b$ must actually be made an instant before the connection to $a$ Is broken? [duplicate]
In Resnick halliday, student 10th edition page - 795. In the topic current decay in RL circuit, the following statement is used, the connection to b must actually be made an instant before the ...
- 43
0
votes
1
answer
123
views
In The question given below, why the length for calculating reluctance is taken by those dotted lines?
The question is as follows:
For the core shown in Fig. 3.20, it is required to produce a flux of 2 mWb in the limb CD. The entire core has a rectangular cross section of 2cm × 2cm. The magnetizing ...
- 31
1
vote
1
answer
80
views
Physics HL IB 2008: Transformer currents question
A question on the IB HL Physics paper of a couple of years back looks like this:
In the second image, taken from this video solution, you see that the given answer should be D.
Now, I have an issue ...
- 319
2
votes
1
answer
839
views
What will happen to the bulb of the circuit after closing the switch? [closed]
Say it connects a bulb with the circuit below, with the switch $S$ open. Every cable has negligible resistance and the battery has no internal resistance.
What happens to the brightness of the bulb ...
- 23
0
votes
3
answers
475
views
What is the formula for total reactance?
Total Reactance is the sum of capacitive reactance and inductive reactance. So, it should be given by the formula
$$X = X(L) + X(C) \, ..$$
However, in some sources it is
$$X = X(L) - X(C)$$
Which one ...
user355398
1
vote
1
answer
178
views
What happens if a charged capacitor is connected to the ground on both sides through resistors? [closed]
Imagine we have the circuit below:
When the switch is connected to (a), we will be charging the capacitor. After the capacitor is fully charged, the left side of capacitor will be at 5V and right ...
- 113
0
votes
1
answer
106
views
How to find current density given resistor, and voltage, using Ohm's law in this case?
I was wondering about how to find current density, given a resistor and an electromotive force.
resistor's data are: resistivity = $\rho$, length = $l$, and cross sectional area = $A$.
resistor = $\...
0
votes
2
answers
333
views
How much can we push the plates of capacitor?
I am currently a highschooler and came across this question in physics
A capacitor of plate area $A$ and separation $d$ is connected to battery of emf $V$ and is charged to steady state. Now the ...
- 3
2
votes
3
answers
66
views
How does the actual power of the device depend on the angular frequency of the voltage? [closed]
The voltage source produces a sinusoidal AC voltage. An electrical device with resistance and inductance is connected to the source. How does the actual power of the device depend on the angular ...
user331916
1
vote
0
answers
408
views
Capacitance of a thin conducting ring
I am following an exercise in which the capacitance of a thin ring is computed. The ring has radius $b$ and thickness $2a$ where $a<<b$.
In this exercise they compute the potential due to a ...
- 735