Q: Given the formula for resolution $$d = \frac{0.5 \lambda}{A.N.}$$, what is the resolving power (d) of a microscope using light with $$\lambda = 550 nm $$and a numerical aperture (A.N.) of 1.25?

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

Q: Which of the following is the correct formula for calculating the total magnification of a compound microscope?

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

Q: A student is using a 4X objective and a 10X ocular lens. What is the total magnification, and what type of observation is this setting best for?

$$4 \times 10 = 40$$; best for scanning and locating the specimen.

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 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 is the resolving power (d) of a microscope using light with $$\lambda = 550 nm $$and a numerical aperture (A.N.) of 1.25?

Accepted Answer

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

Question 4

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

Accepted Answer

It reduces light refraction and increases the amount of light entering the lens, improving resolution.

Question 5

If you increase the magnification on a compound microscope, what happens to the field of view?

Accepted Answer

The field of view decreases.

Question 6

A student observes two points under a microscope and cannot distinguish them as separate objects. What property of the microscope is limiting this observation?

Accepted Answer

Resolution

Question 7

Which of the following is the correct formula for calculating the total magnification of a compound microscope?

Accepted Answer

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

Question 8

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

Accepted Answer

Condenser

Question 9

A student is using a 4X objective and a 10X ocular lens. What is the total magnification, and what type of observation is this setting best for?

Accepted Answer

$$4 	imes 10 = 40$$; best for scanning and locating the specimen.

Question 10

Which of the following best explains why the use of immersion oil increases the resolution of a microscope?

Accepted Answer

Immersion oil has a refractive index similar to glass, reducing light refraction and increasing the numerical aperture.

Question 11

If the numerical aperture (A.N.) of a lens is increased while keeping the wavelength constant, what happens to the resolving power (d)?

Accepted Answer

The resolving power (d) decreases, allowing finer details to be seen.

Question 12

Which of the following is NOT a correct safety or care practice when using a compound microscope?

Accepted Answer

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

Question 13

Which of the following best describes the relationship between wavelength ($$\lambda) $$and resolution in light microscopy?

Accepted Answer

Shorter wavelengths result in better (lower) resolution values.

Question 14

A student observes a specimen under 100X total magnification and then switches to 1000X total magnification. What happens to the field of view and the amount of detail visible?

Accepted Answer

The field of view decreases and more detail is visible.

Question 15

Which of the following best explains why bacteria are typically observed using the 100X objective lens with oil immersion?

Accepted Answer

Bacteria are very small and require high magnification and resolution to be seen clearly.

Question 16

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

Accepted Answer

Start with the lowest objective, use coarse focus, switch to higher objectives, use fine focus.

Question 17

If a student uses a microscope with a 10X ocular and a 100X oil immersion objective, what is the total magnification and what is the main advantage of using oil immersion?

Accepted Answer

$$10 	imes 100 = 1000$$; oil immersion increases resolution by reducing light refraction.

Question 18

Which of the following statements about the diaphragm in a compound microscope is correct?

Accepted Answer

The diaphragm controls the amount of light and contrast passing through the specimen.

Question 19

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).

Microscopio Compuesto de Campo Claro y Morfología de Bacterias: Guía de Estudio

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