"R" is used as an abbreviation, probably because it is the first letter of "resistance".
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.
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.
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.
The formula is Resistance= Voltage/ Amps(current) In your example: R=50/2.5, so the answer is 20 ohms.
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.
R=i/v If R = resistance, i = current and v = voltage, the formula is incorrect. It should be: R = v/i
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.
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.
Your current will be 30/R Amps. Where R is the resistance in Ohms.
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.
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
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
it's generally the resistance. its generally the energy dissipiating component called Resistor
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.
Resistance is resistance , no matter if it is contact resistance or any other resistance. And formula is R = V / I.
R stands for the 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