MCQ
The relation among $u, v$ and $f$ for a mirror is:
- ✓$\text{f}=\frac{\text{uv}}{\text{u+v}}$
- B$\text{v}=\frac{\text{fu}}{\text{u+f}}$
- C$\text{u}=\frac{\text{fv}}{\text{f+v}}$
- DAll of these
✓
Answer
Correct option: A.
$\text{f}=\frac{\text{uv}}{\text{u+v}}$
As we know,
$\frac{1}{\text{f}}=\frac{1}{\text{v}}+\frac{1}{\text{u}}$
$\frac{1}{\text{f}}=\frac{\text{u+v}}{\text{uv}}$
$\text{f}=\frac{\text{uv}}{\text{u+v}}$
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