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11

Question: Which of two pipes of equal length offers less resistance to the flow of water, one of which has twice the cross sectional area of the other? Answer: The one of twice the cross sectional area. But the one of twice the cross sectional area can be thought of as two of the smaller cross sectional area pipes in parallel. This analogy gives an idea of ...


8

Suppose you have a voltage $V$ between two points A and B in a circuit. If initially you have a resistor of resistance $R_1$ between A and B, the current flowing through the resistor is $I_1=V/R_1$. Now if you connect another resistor $R_2$ in parallel to the resistor $R_1$, then the former will have the same voltage $V$ across it (since it is connected to ...


6

Imagine a block sliding down a slope and that there is an amount of friction between the slope and the block such that the block slides down the slope at constant speed. As the block slides down the slope it loses gravitational potential energy and an equal amount of heat is generated due to the friction between the slope and block. The block does not ...


5

If I have a circuit with resistance R and voltage V, I get a certain current - that's Ohm's law, $I = \frac{V}{R}$. Now imagine you have two such circuits - completely separate from each other. Each will have the same current. Let's say the voltage is 1 V, and the resistance is 1 A: Now if I connect the terminals of the two voltage sources together (...


3

It seems like you get the rational answer but lack the ability to feel it: imagine you have 5 doors of different sizes and a thousand people to pass from a to b. If all the doors are in a row (so everyone has to pass every door), it will take a lot more time compared to the situation, where you place all the doors next to each other so that every person can ...


3

Let the potential difference $V$ is equal to sum of potential difference $V_1,V_2...$ In series connection $$V=V_1+V_2..$$ $$V=IR_1+IR_2...$$ $$IR=IR_1+IR_2...$$ Therefore the equivalence resistance, $$R_S=R_1+R_2...$$ ,which always greater than individual resistance While in parallel combination $$I=I_1+I_2+...$$ $$=>~~~~I=\frac {V}{R_1} +\frac {V}{R_2}...


3

If you remove all resistors the voltage drop will be across the wire. (Because the wire probably has a very small resistance the current through the wire will be very big and the wire will get very hot). if there are resistors in series connected by wires, the resistance of the wires is usually neglected. You can easily see that this is reasonable because ...


3

I tend to agree with Sanya in that I am not sure about the universality of this. There might of course be instances where this is the case. A pure metal has a periodic lattice of ions. There is then a conduction band of electrons that fills the space between the ions. These electrons have wave vectors in the reciprocal space. In space the occurrence of ...


2

The range of a given voltmeter can both be increased and decreased. We know that for converting a galvanometer of resistance $G$ into a voltmeter of range $V$, a high resistance $R$ given by $$R = \frac{V}{I_g}-G$$ has to be connected in series to the coil of the galvanometer. In order to increase the range of the voltmeter, R has to be increased. It ...


2

It is the same thing. $V$ being proportional to $I$ means that $I$ is proportional to $V$. But the proportionality constants are different, so the law might have been set up in the simplest possible way as $$V=RI$$ instead of $$I=\frac{1}{R}V$$ Direct proportionality is seen in both cases, $V\propto I$ and $I\propto V$, just with different ...


2

First of all, I want to see an (experimental) proof that any metal has a higher resistance than any alloy (at any pressure, temperature and volume). What I presume your teacher might have wanted to hear is something along the following lines: a perfect, perfectly static crystal would be, if I remember correctly, perfectly transparent to an electron, so there ...


3

I'm surprised that no one has yet mentioned the hydraulic analogy for electricity to help the OP understand better. A brief summary of this analogy is: Electricity is like water flowing through pipes. Current = amount of water flowing through pipe Voltage = pressure of water Power = water pressure x water flow (voltage x current) Resistors = constrictions ...


1

But if the amount of current flowing into the filament of the bulb = the amount of current flowing out of the filament and at the same time it is producing photons(light energy) [and some heat energy too] then aren't we creating energy ? Which is not possible. Current is the flow of charge over time , Q/t. It can be larger of smaller depending on the ...


1

If the amount of electrons remain the same, where does the energy come from? Batteries have energy stored inside. The energy inside a battery could accelerate electrons to a very high velocity. However, this doesn't happen in a circuit. Just as the battery speeds up an electron, the electron hits to another one and remains constant speed. So the battery ...


1

From the wording of the question I would assume the OP didn't want formulas or a very technical answer, so I'll attempt answering in layman's terms. What does resistance do? It resists the flowing of current. Given the same voltage, the bigger the resistance, the smaller amount of current can flow. Now, imagine that there is a resistor. You put another one ...


1

When dealing with inductors Sears & Zemansky state that "we need to develop a general principle analogous to Kirchhoff's loop rule". With an inductor present in the circuit they state that there is a non-conservative electric field within the coils $\vec E_n$ as well a conservative electric field $\vec E_c$. Assuming that the inductor has negligible ...


1

If you're considering the following: then the resistance between the ends is $1 + \frac{1}{2} + \frac{1}{3} + \cdots $ which doesn't converge.


1

My answer is r. 2 resistances on the vertical line are redundant as no current flows via that route due to the symmetry of the problem. Consider this circuit joined to the source with A joined to the positive terminal, then current will equally split along two possible routes from A. Due to symmetry of the problem, the electric potential energy above the ...


1

As far as I can see the steps you can do are the following: Find voltage over $R_3$ with Ohm's law. Find voltage over the parallel portion with Kirchhoff's voltage law. Find current through $R_2$ with Ohm's law. Find current through $R_1$ with Kirchhoff's current law. Rind resistance $R_1$ with Ohm's law. In short the laws... Ohm's law (for a component)...


1

I think it is easy to solve this puzzle dont assume $R_0$ to be anything, Just use $R$ and $R_T$ for resistance at current temperature $(T)$ and at triple point $(T_T)$. now $R-R_0=R_0\alpha(T-T_0)$ and $R_T-R_0=R_0\alpha(T_T-T_0)$ now divide two expressions and do some basic math and you will get equaiton 1


1

Resistors are in series if they are connected "end-to-end." In a series configuration, the current that flows through one resistor is the same as the current flowing through the other because that current has no where else to go. In this configuration, the voltage across the entire circuit is divided between the resistors. Resistors are in parallel if ...



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