Find the radius of circle of illuminance, if a luminous object is placed at a distance `h` form the interface in denser medium.

Explanation

To find the radius of the circle of illuminance when a luminous object is placed at a distance \( h \) from the interface in a denser medium, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Setup**:
- We have a luminous object in a denser medium with refractive index \( \mu_d \) and a rarer medium with refractive index \( \mu_r \).
- The luminous object is placed at a height \( h \) above the interface between the two media.

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