Question

What is the effective resistance when two resistance of 10 ohm and 15 ohm are connected in parallel

Answer 1

Given:

• Two resistors
• Resistor 1 = 10 ohm
• Resistor 2 = 15 ohm
• Connected in parallel

To find:

• Effective resistance

Solution:

We know that if two resistors are connected in parallel

1/Rp = 1/R1 + 1/R2

→ 1/Rp = 1/10 + 1/15

→ 1/Rp = 0.166 ohm

→ Rp = 1/0.166

→ Rp = 6.024 ohm

Answer 2

In the above Question we have to find the following -.

What is the effective resistance when two resistance of 10 ohm and 15 ohm are connected in parallel ?

Solution -

We know the following for resistances connected in parallel -

For a n number if resistance connected in parallel -

[ 1 / Equivalent Resistance ]

=> [ 1 / R1 ] + [ 1 / R 2 ] + [ 1 / R3 ] + .............. + [ 1 / R n ]

Now , in this question b, we have the following values -

There are two resistances of 10 Ohm and 15 Ohm connected in parallel -

=> [ 1 / Equivalent Resistance ]

=> [ 1 / 10 ] + [ 1 / 15 ]

Now , take LCM

=> [ 3 + 2 ] / [ 30 ]

=> [ 5 / 30 ]

=> [ 1 / 6 ]

Thus -

[ 1 / Equivalent Resistance ] = [ 1 / 6 ]

Cross multiplying we get -

Equivalent Resistance = 6 Ohm .

This is the required answer .

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Additional Information -

For a n number of resistances connected on series -

Equivalent Resistance = R 1 + R 2 + .......... + R n

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