Q: If the wavelength of light used is $$550\ nm$$ and the numerical aperture is $$1.25$$, what is the theoretical limit of resolution ($$d) $$for the microscope? Use $$d = \frac{0.5 \lambda}{A.N.}.$$

$$d = \frac{0.5 \times 550}{1.25} = 220\ nm$$

Q: Which formula correctly calculates the total magnification of a compound microscope?

$$\text{Total Magnification} = \text{Magnification of Ocular} \times \text{Magnification of Objective}$$

Question 1

Which of the following best describes the difference between magnification and resolution in light microscopy?

Accepted Answer

Magnification is the increase in image size, while resolution is the ability to distinguish two points as separate.

Question 2

A student is using a compound light microscope with a 10X ocular lens and a 40X objective lens. What is the total magnification?

Accepted Answer

$$10 	imes 40 = 400$$

Question 3

Given the formula for resolution $$d = \frac{0.5 \lambda}{A.N.}$$, what happens to the resolution if the numerical aperture (A.N.) increases, assuming wavelength remains constant?

Accepted Answer

Resolution improves (d decreases).

Question 4

Why is immersion oil used with the 100X objective lens in light microscopy?

Accepted Answer

To reduce light refraction and increase the amount of light entering the lens, improving resolution.

Question 5

If the wavelength of light used is $$550\ nm$$ and the numerical aperture is $$1.25$$, what is the theoretical limit of resolution ($$d) $$for the microscope? Use $$d = \frac{0.5 \lambda}{A.N.}.$$

Accepted Answer

$$d = \frac{0.5 	imes 550}{1.25} = 220\ nm$$

Question 6

Which of the following is NOT a correct safety or care procedure when handling a compound microscope?

Accepted Answer

Placing the microscope near the edge of the table for easy access.

Question 7

A student observes a specimen under 4X, 10X, and 40X objectives. What happens to the field of view as magnification increases?

Accepted Answer

The field of view decreases.

Question 8

Which formula correctly calculates the total magnification of a compound microscope?

Accepted Answer

$$	ext{Total Magnification} = 	ext{Magnification of Ocular} 	imes 	ext{Magnification of Objective}$$

Question 9

Which part of the microscope is responsible for concentrating light onto the specimen?

Accepted Answer

Condenser

Question 10

A student is trying to distinguish two points that are 0.15 μm apart using a light microscope. If the microscope's resolution limit is 0.2 μm, what will the student observe?

Accepted Answer

The two points will appear as one (unresolved).

Question 11

Which of the following best explains why the image moves in the opposite direction when you move the slide on the stage of a compound microscope?

Accepted Answer

The lenses invert and reverse the image due to the optical path.

Question 12

Which of the following bacterial arrangements is described as spherical cells in clusters?

Accepted Answer

Staphylococci

Question 13

If you want to observe the fine details of a bacterial cell wall, which objective lens should you use and why?

Accepted Answer

100X with immersion oil, because it provides the highest resolution and magnification.

Question 14

Which of the following is the correct order of steps for focusing a specimen under a compound microscope?

Accepted Answer

Start with the lowest power objective, use coarse focus, then fine focus, and increase magnification as needed.

Question 15

Which of the following statements about numerical aperture (A.N.) is correct?

Accepted Answer

Numerical aperture is a measure of the lens's ability to gather light and resolve fine specimen detail at a fixed object distance.

Question 16

Which of the following is a correct conversion from micrometers to nanometers?

Accepted Answer

1 \mu m = 1 	imes $$10^3 nm$$

Question 17

A student observes a bacterial sample and notes that the cells are rod-shaped and arranged in chains. What is the correct term for this morphology and arrangement?

Accepted Answer

Streptobacillus

Question 18

Which of the following best describes the effect of using a shorter wavelength of light in microscopy?

Accepted Answer

It increases the resolution (smaller d value).

Question 19

Which part of the microscope should only be used with the lowest power objective to avoid damaging the slide or lens?

Accepted Answer

Coarse adjustment knob

Question 20

A student is viewing a stained bacterial sample under 1000X total magnification. Which combination of lenses is being used?

Accepted Answer

10X ocular and 100X objective

Microscopio Compuesto de Campo Claro y Morfología de Bacterias

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