Question

If Two Resistors R1 and R2 are connected in series then Req is 10 ohm if connected in parallel then Req = 7.5 ohm. Then find the R1 and R2​

Answer 1

AnSwEr

${\tt{\red{\underline{\large{Given}}}}}$

• Two resistors
• R1 and R2
• Connected in series
• or //
• In series it give = 10
• in \\ = 75/10

${\sf{\green{\underline{\large{To\:find}}}}}$

• Value of R1 and R2

${\sf{\pink{\underline{\Large{Explanation}}}}}$

• we know that in series
• we add directly for Req

R1 +R2 = 10________(1)

Now from //

1/R1 + 1/R2 = 10/75

=>(R1 + R2)/ R1×R2 =10/75 (R1+R2 =10)

=>R1×R2 = 10/75 × 1/10

=>1/ (R1×R2)= 1/75

=>(R1×R2)= 75

For getting R1 and R2

• We have to find (R1-R2)

(R1-R2)²=(R1+R2)²-4 R1×R2

¶utting the values

=>(R1-R2)²=(R1+R2)²-4 R1×R2

=>(R1-R2)²=(10)²-4 × 75

=>(R1-R2)² = 100-290

=>R1-R2=√-190

it is not possible

Therefore R1 and R2 have no accurate value.