A torch bulb is rated 2.5V and 750mA. Two identical resistors, each of resistance 2 ohm , are connected in series and parallel to a battery of 12 V Calculate ratio of power consumed in two cases.
Open in App
Solution
IN SERIES
Total Resistance in Series = R₁ + R₂ = 2 + 2 = 4 Ohm
Potential Difference(V) = 12V Current(I)= V/R =12/4 =3Ampere Power = VI = 12*3 =36 Watts
(2) IN PARALLEL 1/R₁ + 1/R₂ = 1/Rₐ (Where Rₐ is the total resistance) 1/2 + 1/2 = 1/Rₐ 2/2 =1/Rₐ 1/1 = 1/Rₐ 1 Ohm = Rₐ
Voltage (V)= 12Volts Current(I)= V/R = 12 Ampere Power= VI = 12*12 = 144 Watt
Power in series : Power in Parallel 36 : 144 1 : 4