A rectangular conducting loop consists of two wires on two opposite sides of length l joined together by rods of length d. The wires are each of the same material but with cross-sections differing by a factor of 2. The thicker wire has a resistance R and the rods are of low resistance, which in turn are connected to a constant voltage source `V_0`. The loop is placed in a uniform magnetic field B at `45^@` to its plane. Find `tau`, the torque exerted by the magnetic field on the loop about an axis through the centres of rods.

Explanation

To solve the problem of finding the torque \(\tau\) exerted by the magnetic field on the rectangular conducting loop, we will follow these steps:

### Step 1: Understand the Configuration
We have a rectangular conducting loop with:
- Length of the sides: \(l\) (length) and \(d\) (width).
- Two wires of the same material but different cross-sectional areas, where the thicker wire has resistance \(R\) and the thinner wire has resistance \(2R\).
- The loop is connected to a constant voltage source \(V_0\) and placed in a uniform magnetic field \(B\) at \(45^\circ\) to its plane.

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