(a) The given figure shows three resistors. Find the combined resistance.

(b) Which part of an electrical appliance is earthed?

(a) In the circuit, there are two parts. In the first part, resistors of R₁ (6 Ω) and R₂ (2 Ω) are connected in parallel. If the equivalent resistance of this part is R_p then

$\dfrac{1}{{R}$P} = \dfrac{1}{6} + \dfrac{1}{2} \\[0.5em] \dfrac{1}{{R}P} = \dfrac{1 + 3}{6} \\[0.5em] \dfrac{1}{{R}P} = \dfrac{4}{6} \\[0.5em] \dfrac{1}{{R}P} = \dfrac{2}{3} \\[0.5em] \Rightarrow {R}_P = \dfrac{3}{2} = 1.5 Ω

Hence, R_P = 1.5 Ω

In the second part, R_P (1.5 Ω) and R₃ (6 Ω) are connected in series. If the equivalent resistance of this part is R_s then

R_s = (1.5 + 6) Ω = 7.5 Ω

Hence, combined resistance = 7.5 Ω

(b) The earth wire is connected to the metallic body of the appliance.