B1.1

Question 1

What is the primary purpose of using a microscope when studying cells?

Answer 1

To observe cells, which are too small to be seen with the naked eye, and to study their structures.

Question 2

Explain how magnification is calculated in a light microscope. Include an example.

Answer 2

Magnification is calculated by multiplying the magnification of the eyepiece lens by the magnification of the objective lens.
Example: If the eyepiece lens is x4 and the objective lens is x10, the total magnification is:
4 × 10 = 𝑥40

Question 3

State the main difference in magnification power between a light microscope and an electron microscope.

Answer 3

Light microscopes can magnify up to around 𝑥2000.
Electron microscopes can magnify up to x200,000.

Question 4

Define resolving power and explain its significance in microscopy.

Answer 4

solving power is the ability to distinguish between two separate points that are close together. It determines the level of detail visible in the image. A higher resolving power allows for clearer and more detailed images.

Question 5

Describe one advantage and one disadvantage of using a Light microscope

Answer 5

Advantage: Relatively cheap and can be used almost anywhere.
Disadvantage: Low magnification and resolving power compared to electron microscopes.

Question 6

Describe one advantage and one disadvantage of using Electron microscope

Answer 6

Advantage: Very high magnification and resolving power, allowing for detailed views of subcellular structures.
Disadvantage: Expensive and requires special temperature, pressure, and humidity-controlled rooms.

Question 7

Convert 1 micrometer (μm) into nanometers (nm).

Answer 7

1μm=1000nm.

Question 8

A student observes a cell under a microscope with a magnification of x40. If the measured size of the cell image is 1 mm, what is the actual size of the cell?

Answer 8

Actualsize= Magnification / Sizeofimage
​
= 1mm/40
​
=0.025mmor25μm.

Question 9

Why do electron microscopes require special conditions, such as pressure and temperature control?

Answer 9

Because they use a beam of electrons to form an image, which requires specific environmental conditions to function properly and avoid interference.

Question 10

How does a transmission electron microscope differ from a scanning electron microscope in terms of the images it produces?

Answer 10

Transmission electron microscopes (TEM) produce 2D images with very high magnification and resolution.

Scanning electron microscopes (SEM) create dramatic 3D images of surfaces.