Calculator for ac Resistance of a Round Straight Wire
electrical resistance of a wire - The Physics Classroom
When a cylindrical sensor is placed so that its axis is not perpendicular to the flow direction, there will be a component of velocity that is parallel to the axis of the sensor. If the sensor has infinite length, then the effective cooling velocity that the sensor experiences is that which is perpendicular to the sensor; the parallel component has no effect. Thus, the effective cooling velocity ueff may be obtained from the expression
A spell is a one-time magical effect
In use, errors arise due to changes in ambient temperature and other fluid properties, and due to the deposition of impurities in the flow on the sensor. Standard procedures are available to correct for the effects of changes in temperature. The time for which a calibration is valid depends on the individual situation. In high speed wind tunnels, large particles can remove a wire with annoying frequency.
Cyberphysics - Factors that affect the resistance of a wire
So, to illustrate Ohm's law, let's consider a speaker circuit, and we'll suppose, for the sake of this example, that the installer has decided to use a dramatically undersized speaker cable. Each conductor of this cable has a resistance of four ohms, and the speaker has an impedance of eight ohms. Signal coming from one speaker terminal and traveling to the other will go through four ohms of speaker wire resistance, through an eight-ohm speaker, and then through another four ohms of speaker wire resistance. What does this mean? The total circuit resistance is 16 ohms (to simplify matters, we're going to assume a zero ohm "output impedance"; this isn't realistic, but is good enough to illustrate the principles at work here). So, of the energy being burned up in the circuit, one quarter (4 ohms over 16 ohms) is burned up on the way from the "plus" terminal to the speaker; one half (8 ohms over 16 ohms) is delivered to the speaker; and one quarter is burned up on the other side of the speaker cable, between the speaker and the "minus" terminal of the amp.