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"R" is used as an abbreviation, probably because it is the first letter of "resistance".

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What is the formula for calculating the resistance in an electrical circuit?

The formula for calculating resistance in an electrical circuit is R V/I, where R is the resistance, V is the voltage, and I is the current.


There is a current of 0.83 A through a light bulb in a 120 V circuit What is the resistance of this light bulb?

If a lightbulb has a resistance of 250 ohms, the voltage required for the bulb to draw a current of 0.5 A is 125 V. (Ohm's law: voltage equals current times resistance)Unfortunately, its more complicated than that...Is the resistance of 250 ohms the hot resistance or the cold resistance? It matters. It matters very much.Light bulbs have a dramatic positive resistance to temperature coefficient. It is not uncommon for the instantaneous on power to be 10 or 20 times the nominal value.So, if the 250 ohms is the measured resistance while operating at a current of 0.5 A, then 125 V is the correct answer. If the resistance is the cold resistance, you need to go back and find out the hot resistance at the desired operating point.


How do you find resistance in a circuit?

That entirely depends on whether the resistances are in series or in parallel with each other. Ohm's law states that I=V/R. i.e. current = voltage/resistance. If you know the current and voltage you can find the resistance. You can use algebra to rearrange the formula for R and get that R= V/I. Resistance = voltage/current.


An electric appliance draws 1.5 amperes of current when it is connected to a 24-volt source - What is the resistance of this appliance?

The formula is Resistance= Voltage/ Amps(current) In your example: R=50/2.5, so the answer is 20 ohms.


How would resistance r depend on cross section and length of the material?

Resistance R =p(L /A)i,e Resistance(R) of a conductor will be directly proportional to its length(L) ==> if the length of the conductor increases its resistance also will increase.i,e Resistance(R) of a conductor is inversely proportional to its cross section area(A) ==> if the Area of the conductor increases its resistance also will decrease.

Related Questions

How do you test for resistance?

R=i/v If R = resistance, i = current and v = voltage, the formula is incorrect. It should be: R = v/i


What is resistance measured in a unit called?

Ohms. It can also be calculated using Ohm's Law. V=I/R where V is voltage in Volts, I is current in Amps, and R is resistance in Ohms.


Which resistance will be maxium in a circuit 'r' or 'R'?

There is no relation between the value of a resistance and whatever name you choose to call such a thing. But traditionally, for obvious reasons, use of the small letter r means there is an expectation that it will be smaller than one called R.


A wire with resistance R is connected to the terminals of a 30 V battery. What is the current through the wire if the wire has the resistance?

Your current will be 30/R Amps. Where R is the resistance in Ohms.


What does resistance in wire depend on?

Resistance is directly proportional to the resistivity and length of the conductor, and inversely-proportional to its cross-sectional area. As resistivity is affected by temperature, we can say that temperature indirectly affects resistance.


What is the unit of measurement of internal resistance?

unit of internal resistasnce is ohms too. V = I(R+r) V voltage across the circuit I current in the circuit R external resistance r internal resistance unit of internal resistasnce is ohms too. V = I(R+r) V voltage across the circuit I current in the circuit R external resistance r internal resistance


Is current the voltage multiplied by resistance?

No. V =Voltage, I =current, and R =resistancein the simple equation: V=I*R. As well, V/I=R, and. V/R=Iso Current is voltage divided by resistance


What does R mean in an electrical circuit?

it's generally the resistance. its generally the energy dissipiating component called Resistor


What is the formula for calculating the resistance in an electrical circuit?

The formula for calculating resistance in an electrical circuit is R V/I, where R is the resistance, V is the voltage, and I is the current.


How do you calculate contact resistance?

Resistance is resistance , no matter if it is contact resistance or any other resistance. And formula is R = V / I.


What does r mean in a resistor?

R stands for the resistance.


What are the rules for electricity resistance?

Resistance of a conductor is defined by the specific resistivity, area of cross section and the length of the conductor. R = rL/A, where R is resistance in OHMs, r is specific resistance, L length in mm, A is area of cross section in sq mm