the resistance of 2 wires is 25 ohms when connected inseries and 6 ohms when joined in parallel.the resistance of each wire is
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Given,
Rs=R1+R2
=25=R1+R2 -------¹
R1=25-R2 ---------²
now,
1/Rp=1/R1+1/R2
1/6=1/R1+1/R2
placing value of R1 from ²
1/6 = 1/25-R2 +1/R2
1/6 = R2+25-R2 / 25R2- R2²
by cross multiplying
1×(25R2-R2²) = 6×(25)
-R2²+25R2=150
-R2²+25R2-150=0
by factorising
-R2²+10R2+15R2-150=0
-R2(R2-10)+15(R2-10)=0
(-R2+15)(R2-10)=0
R2=10 & R2=15
Now, if R2 is 10, then from equation ¹, R1 is 15 ohm
and if R2 is 15, then R1 is 10 ohm. answer
Rs=R1+R2
=25=R1+R2 -------¹
R1=25-R2 ---------²
now,
1/Rp=1/R1+1/R2
1/6=1/R1+1/R2
placing value of R1 from ²
1/6 = 1/25-R2 +1/R2
1/6 = R2+25-R2 / 25R2- R2²
by cross multiplying
1×(25R2-R2²) = 6×(25)
-R2²+25R2=150
-R2²+25R2-150=0
by factorising
-R2²+10R2+15R2-150=0
-R2(R2-10)+15(R2-10)=0
(-R2+15)(R2-10)=0
R2=10 & R2=15
Now, if R2 is 10, then from equation ¹, R1 is 15 ohm
and if R2 is 15, then R1 is 10 ohm. answer
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