Question

In a Wheatstone bridge with \[R_1 = 200 \Omega\], \[R_2 = 300 \Omega\], and \[R_3 = 120 \Omega\], what is the value of the unknown resistance \[R_4\]?

Options

• 180 Ω

• 200 Ω

• 150 Ω

• 160 Ω

Answer 1

Using the balance condition formula \[R_4 = \frac{R_2 \times R_3}{R_1} = \frac{300 \times 120}{200} = \frac{36000}{200} = 180 \Omega\]. Therefore, the unknown resistance \[R_4\] is 180 Ω when the bridge is balanced.