A cell of internal resistance r supplies current to a 6.0Ω resistor and its efficiency is 75%. Find the value of r.

ngenebenjamin

3 years ago

Efficiency = out put/ input ×100/1
Output Power=6
Input Power=power + that due to internal resistance
75%=6/(6+r)×100/1


i.e 75/100 = 6/(6+r)

75 (6+r) = 100/*6

i.e 450 + 75r = 600
75r =600 - 450
i.e r = 150/75 = 2Ω
i.e r = 2Ω

Isaac.Newton

11 years ago

E=R / r+R.

0.75=6/{r+6} ,6/0.75={r+6}

r=8-6=2

Tokewins

3 years ago

This is the explanation