Hema uses two appliances in her home. One appliance is rated at 100 W and operates at 220 V, while the other appliance is rated at 60 W and also operates at 220 V. These appliances are connected to the electrical main supply in both series and parallel configurations, as shown in the figure 1 and 2.

(a) Calculate the total power consumption when the two appliances are connected in series.

(b) Calculate the total power consumption when the two appliances are corrected in parallel.

(c) Which configuration results in higher total power consumption, series or parallel?

(a) Given,

P₁ = 100 W

P₂ = 60 W

V = 220 V

We know, R₁ = $\dfrac{V$1^2}{P1}

= $\dfrac{220^2}{100}$

= $\dfrac{48400}{100}$

= 484 Ω

R₂ = $\dfrac{V$2^2}{P2}

= $\dfrac{220^2}{60}$

= $\dfrac{48400}{60}$

= 806.6 Ω

Total resistance = 484 + 806.6 = 1290.6 Ω

∴ Total power consumption in series = P_total = $\dfrac{V^2}{R_{total}}$

= $\dfrac{220^2}{1290.6}$ = 37.5 W

Hence, total power consumed = 37.5 W.

(b) When the appliances are connected in parallel,

P_total = P₁ + P₂ = 100 W + 60 W = 160 W

(c) Parallel configuration.