SOLUTION

Balanced Wheatstone Bridge:

• In a balanced Wheatstone bridge, the ratio of resistances in the two arms is equal. This means:

P/Q = R/S

In this specific case, the values are:

10/30 = 20/60

• When the bridge is balanced, no current flows through the galvanometer. This is because the potential difference across the galvanometer is zero.

2. Current Drawn from the Cell:

• To find the current drawn from the cell, we need to calculate the equivalent resistance of the circuit.
• 30 and 10 ohm resistance is connected in series and 20 ohm and 60 ohm are connected are connected in series.
• The 40 kΩ and 80 kΩ resistors are connected in parallel. The equivalent resistance (Req) of two resistors in parallel is given by:

1/Req = 1/R1 + 1/R2

• So, for the given resistors:

1/Req = 1/40kΩ + 1/80kΩ

Req = 80/3 kΩ

• Now, we can use Ohm’s law to find the current (I) drawn from the cell:

I = V/Req

Where:

• V = Voltage of the cell (24 V)
• Req = Equivalent resistance (80/3 kΩ)
• Substituting the values:

I = 24 V / (80/3 kΩ)

I = 0.9 mA

Therefore, the current drawn from the cell is 0.9 mA.