Question

1. John has placed an object at infinity. A 20 cm converging lens is nearest to the object. A 10 cm diverging lens is placed 20 cm behind the first lens. Does John have a Galilean telescope? Explain your reasoning.
   

2. Where is the object placed relative to the objective lens for a microscope?
   

3. Where is the image formed relative to the objective lens for a microscope?
   

4. Where is the eyepiece placed for a microscope in order for the relaxed eye condition to be met?
   

5. Is the final image of a microscope real or virtual? Explain your reasoning.

6. Is the final image of a microscope magnified or minified? Explain your reasoning
   

7. Is the final image of a microscope upright or inverted? Explain your reasoning.
   

8. Calculate the angular magnification for both combinations of lenses. Make sure to show your work.
   

9. Which lens combination made the best microscope? Explain why you think this was the case.

Answer 1

a) No this is not a Galelian telescope.

For a Galelian telescope, the distance between the two lenses must be equal to the sum of the focal lengths of the lenses.

So, here, the second lens must be placed 30 cm away from the first lens.

b) The object is placed almost at the focus of the objective lens of the microscope.

c) The image from the objective lens is ideally formed between the eyepiece and its focus inside the microscope .

d) The eyepiece must be placed such that the focus of the eyepiece is falling on our eye for a relaxed eye condition to be met.

e) The image is virtual.

For a microscope, the image from the objective lens is ideally formed between the eyepiece and its focus inside the microscope . This image acts as the object for the eyepiece.

This image due to an object palced closer than the focus of a convex lens is virtual.

f) The image is magnified.

The secondary object is between the eyepiece and its focal point. So, the image formed by this will be much larger than the object (also, the basic purpose of a microscope is to magnify)

g) The image is inverted.

The first lens inverts the image. But the second lens form a virtual and erect image. So, the effective image will be inverrted and virtual.