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Resistance Formula

Resistance is the measure of opposition offered by any body to the flow of electric current. A resistor is an electronic component used in the circuit in order to offer that particular amount of resistance.

The resistance across any object is calculated using the formula

Where,
v = Voltage applied across its ends
I = Current flowing through it.

If resistance are connected in series the series resistance is given by

If resistance are connected in parallel the parallel resistance is given by

Where, R1, R2, R3 ...... Rn are the given resistors. The resistance is measure in ohms ($\Omega$).

Resistance Formula is used to calculate the resistance across any given number of resistors in the circuit. It is also used to calculate the resistance in any given body.

Related Calculators
Resistance Calculator capacitor resistance calculator
Equivalent Resistance Calculator resistive voltage divider calculator
 

Resistance Problems

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Below areproblems based on resistance which may be helpful for you.

Solved Examples

Question 1: Calculate the resistance offered by the body if 2mA of current is flowing having potential difference of 2V?
Solution:
 
Given: Current I = 2mA,
          Potential difference V = 2 V
The resistance is given by R = $\frac{V}{I}$
                                          = $\frac{2}{2 \times 10^{-3}}$
                                          = 1000 $\Omega$.
 

Question 2: Calculate the resistance if 5 $\Omega$ and 2 $\Omega$ are connected in parallel.
Solution:
 
Given: Resistance R1 = 5 $\Omega$, R2 = 2 $\Omega$
The parallel resistance is given by
$\frac{1}{R_{p}}$ = $\frac{1}{R_{1}}$ + $\frac{1}{R_{2}}$
Rp = $\frac{R_{1} R_{2}}{R_{1} + R_{2}}$  
     = $\frac{5 \times 2}{5 + 2}$
     = 1.428 $\Omega$.          
 

More topics in Resistance Formula
Equivalent Resistance Formula Resistors in Parallel Formula
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