The critical velocity v for a liquid depends upon (a) coefficient of viscosity `eta` (b) density of the liquid `rho` and © radius of the pipe r. Using dimensions derive an expression for the critical velocity.

Explanation

To derive the expression for the critical velocity \( v \) in terms of the coefficient of viscosity \( \eta \), density of the liquid \( \rho \), and radius of the pipe \( r \), we will use dimensional analysis.

### Step-by-Step Solution:

1. **Identify the Variables**:
The critical velocity \( v \) depends on:
- Coefficient of viscosity \( \eta \)
- Density of the liquid \( \rho \)
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