Size of specimens：练习题

A student observes a bacterial cell under a light microscope. The image of the cell measures 15 mm. If the actual size of the bacterial cell is \(5 \mu\text{m}\), what is the magnification of the microscope?

A bacterium has an actual length of 5 $$\mu \text{m}$$. In a diagram, its length is 20 mm. What is the magnification of the diagram?

An amoeba is observed under a light microscope with a magnification of x400. Its image appears to be 2.8 cm long. What is the actual length of the amoeba in micrometres ($$\mu \text{m}$$)?

A microscopic organism is magnified 500 times. If the image size is 10 mm, what is the actual size of the organism?

A bacterial cell, which has an actual length of \(1.5 \mu\text{m}\), is viewed under a microscope. If the image of the bacterium measures 30 mm, what is the magnification of the microscope?

Convert a measurement of 7.5 millimetres (mm) into micrometres (μm).

Calculate the actual length in micrometres (\(\mu m\)) of a specimen if its image length is 24 mm and the magnification is \(\times 3000\).

A bacterium has an actual length of 2 micrometres (μm). If it is viewed under a microscope with a magnification of x5000, what will be the length of its image in millimetres (mm)?

A student uses a light microscope to observe a specimen of human skin cells. She measures the diameter of one cell in her drawing to be 18 mm. The actual diameter of the cell is known to be \(60 \mu m\).

(a) Using the formula for magnification, calculate the magnification used for this drawing. Show your working.
(b) The student then observes a smaller structure within the nucleus that has an actual length of \(2.5 \mu m\). Calculate the length of this structure in the drawing, in millimetres (mm), if the same magnification is used.

A student views a human liver cell under a microscope. The image of the liver cell measures 45 mm in diameter. The microscope has an eyepiece lens with a magnification of x10 and an objective lens with a magnification of x40.

(a) Calculate the total magnification of the microscope.

(b) Calculate the actual diameter of the human liver cell in micrometres (µm). Show your working.