Question

When no current flowsthrough a cell the pd across its terminal is found to be 6volt when it is connected to a resistance 23.6 ohm the potential difference across its terminals is found to be 5.9 volt what is its internal resistance

Answer 1

Then Denominator=2x+1

Fraction =2x+1x

Reciprocal of the fraction =x2x+1

It is given that the sum fo the fraction and its reciprocal is 22116

∴2x+1x+x2x+1=22116

⇒x(2x+1)x2+(2x+1)2=2158⇒2x2+x5x2+4x+1=2158

⇒21(5x2+4x+1)=58(2x2+x)⇒105x2+84x+21=116x

⇒11x2−26x−21=0⇒11x2−33x+7x−21=0⇒11x(x−3)+7(x−3)=0

⇒(11x+7)(x−3)=0⇒x=3,−117

∵ x can not be a negative

⇒x=3

Hence the fraction =2x+1x=73