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R' is the symbol for resistance in electrical circuits because it represents the opposition to the flow of electric current that a resistor provides. It is a standard notation used in circuit diagrams and equations to represent this fundamental property of resistors in circuits. Calling it "resistance" reinforces the concept that resistors impede the flow of current.
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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?
You can find resistance in a circuit by using Ohm's Law, which states that resistance (R) is equal to voltage (V) divided by current (I), or R = V/I. Alternatively, you can use a multimeter to directly measure the resistance in the circuit.
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 resistance of the appliance can be calculated using Ohm's Law: Resistance (R) = Voltage (V) / Current (I). In this case, R = 24V / 1.5A = 16 ohms.
How would resistance r depend on cross section and length of the material?
Resistance (R) of a material depends on both its cross-sectional area (A) and length (L) according to the formula R = ρ * L / A, where ρ is the material's resistivity. The resistance is directly proportional to the length of the material and inversely proportional to its cross-sectional area. This means that as the length of the material increases, the resistance also increases, while as the cross-sectional area increases, the resistance decreases.
How can you solve for resistance when given power?
You can solve for resistance using the formula ( R = \frac{V^2}{P} ), where R is the resistance, V is the voltage, and P is the power. By rearranging the formula, you can solve for resistance by dividing the square of the voltage by the power.
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 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
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.
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
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
What determines the current of a battery?
its internal resistance V/R= A its internal resistance V/R= A
