Answer to Question #95380 in Optics for jane montgomery

Question

When shining a flashlight through a drinking glass, why does changing the distance of the
flashlight from the glass change the size of the image? Why does it change other details about the
image (such as the blurriness of it)?

When shining the light through the drinking glass, what kind of lens was the glass acting as?
How do you know?

Answer 1

why does changing the distance of the flashlight from the glass change the size of the image?

Answer

Magnification is given by formula

$m=\frac{f}{d}=\frac{H}{h}(1)$

where H is the transverse size of the image, h is the transverse size of the object

In this way, the distance of the flashlight from the glass change the size of the image

Why does it change other details about the image (such as the blurriness of it)?

Answer

Aberration (comatic aberration, chromatic aberration) affects the image

what kind of lens was the glass acting as?

Answer

The drinking glass acts as a converging lens.

In this case, we can write

$\frac{1}{f}=\frac{1}{v}+\frac{1}{u} (1)$

where f the focal length of the glass, v is the distance from the glass to object, u is the distance from the glass to image