2.1.1 (e,f) Magnification and resolution

What is the best definition of resolution?

• Ability to distinguish between objects that are close together

• How many times larger the image is than the actual size of the specimen

• Ability to zoom more closely into an image.

• Ability to see a specimen at high magnification.

Which is the correct formula for calculating image size?

• Image size = actual size x magnification

• Image size = actual size / magnification

• Image size = magnification / actual size

Which unit would be most appropriate for measuring the length of an average plant cell?

• cm (centimetres)

• mm (millimetres)

• nm (nanometres)

• μm (micrometres)

Students measure a structure as 12 mm long in a micrograph - its actual size is 29.8 μm. What approximate magnification is being used? (NB you can do this in your head!)

• 40x

• 300x

• 400x

• 3000x

How would you convert cm to μm?

• Multiply by 1,000.

• Divide by 1,000.

• Multiply by 10,000.

• Divide by 10,000.

A magnified image is 8 mm wide and the magnification is ×40. What is the actual size?

• 0.02 mm

• 200 μm

• 20 μm

• 0.002 mm

Convert 10mm to μm.

• 10,000 μm

• 0.01 μm

• 100 μm

• 1 μm

Under x400 magnification a root hair measures 60mm in length. What is the actual length of the root hair cell? Give your answer in standard form.

• 0.15 mm

• 1.5 x 10¹ mm

• 1.5 x 10^-1 mm

• 1.5 mm