Question

Two identical resistors of 12 ohms each connected to a battery of 3V. Calculate the ratio of the power consumed by the resulting combinations with minimum resistance and maximum resistance

Answer 1

Power=v×v/r

So resistance 1 is 6ohm

Resistance 2 is 24 ohm

Voltage of 3volt

Power1 is 3×3/6=1.5 ohm

Power2 is 3×3/24=0.3ohm

To find ratio of power1 and power2

Therefore the ratio is 5:1

Answer 2

Answer:

4 : 1

Explanation:

At maximum resistance the resistors should be connected in series whereas at minimum resistance the resistors should be connected in parallel.

Effective resistance when resistors are connected in :

1) Series = R1 + R2

2) parallel = 1/R1 + 1/R2

Power = V²/R

Series :

V = 3

R(E) = 12 + 12 = 24

P = 3²/24 = 0.375

Parallel :

1/12 + 1/12 = 2/12 = 1/6

R(E) = 6

P = 3²/6 = 1.5

Power at minimum resistance : maximum resistance.

1.5 : 0.375

= 4 : 1