MCQ
An object is placed at a distance u from a simple microscope of focal length f. The angular magnification obtained depends:
- AOn f but not on u.
- BOn u but not on f.
- ✓On f as well as u.
- DNeither on f nor on u.
✓
Answer
Correct option: C.
On f as well as u.
The angular magnification is the ratio of the angle subtended by the image to the angle subtended by the object on an unaided eye.
In a simple microscope,
$\text{m}=\frac{\frac{\text{h}}{\text{x}}}{\frac{\text{h}}{\text{D}}}$
Here,
u = Object distance from the lems
D = Image distance form the lens
h = Height of the object
In normal adjustment, the object is placed at a distance equal to focal length (f) from the lens and then magnification is given by m
$=\frac{\text{D}}{\text{f}}$
for $\text{u}<\text{f},\text{ m}=\frac{\text{D}}{\text{f}}+1$
In a simple microscope,
$\text{m}=\frac{\frac{\text{h}}{\text{x}}}{\frac{\text{h}}{\text{D}}}$
Here,
u = Object distance from the lems
D = Image distance form the lens
h = Height of the object
In normal adjustment, the object is placed at a distance equal to focal length (f) from the lens and then magnification is given by m
$=\frac{\text{D}}{\text{f}}$
for $\text{u}<\text{f},\text{ m}=\frac{\text{D}}{\text{f}}+1$
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