Five resistors, each of 3 ohm, are connected as shown in figure. Calculate the resistance (a) between the points P and Q, and (b) between the points X and Y.

According to the question,

(a) R₁ = 3 + 3

R₁ = 6 ohm

R₂ = 3 ohm

R₁ and R₂ are joined in parallel

1 / R = 1 / R₁ + 1 / R₂

1 / R = 1 / 6 + 1 / 3

1 / R = (1 + 2) / 6

1 / R = 3 / 6

1 / R = 1 / 2

R = 2 ohm

(b)So since, R = 2 ohm

R₃ = 3 ohm

R₄ = 3 ohm

R’ = R + R₃ + R₄

R’ = 2 + 3 + 3

R’ = 8 ohm