Two electric lamps are rated as 220V,100W and 220V, 40W respectively. Their electric resistances are

Options

A. `484 Omega,1210 Omega`
B. `2.2 Omega,5.5 Omega`
C. `45.5 Omega 7.3 Omega`
D. 100W,40W

Explanation

Resistance `R=V^2/P` where V= Voltage /potential difference and P=power
`therefore` electrical resistance of 100W lamp `R_1=V^2/P_1=(220 times 220)/100=484 Omega`
and electrical resistance of 40W lamp, `R_2=V^2/P_2=(220 times 220)/40=1210 Omega`