PB15.0 Resolving power

Let's review and get ready for today's class！😊​

· Full wavelength difference

Tommy​ Xu

​The interference and diffraction effects have consequences for the development of optical instruments. The diffraction produced by a single circular aperture consists of concentric light and dark bands. (see the graph on the right)

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If the aperture increases in size the width of the central maximum and the size of the diffraction pattern decrease.

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Some text here about the topic of discussion

The resolving power of an instrument is the angular separation of the sources, which enables you to tell you are viewing two sources.

​What the textbook said:

​Rayleigh Criterion

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• ​θ is the angle subtended between the sources measured in seconds of arc​

• λ is thewavelength of the light used in metres​

• d is the diameter of the aperture in metres.

Easy right? Let's see 😊

What is the resolving power of the Hubble space telescope, which has an aperture of 1.8 m, when viewing two sources of red light of wavelength 650 nm?

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​Find the resolving power of a microscope whose objective lens is 0.50 cm in diameter

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(a) when blue light of 450 nm is used to illuminate the two sources;

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(b) when red light of 650 nm is used to illuminate the two sources.

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(c) Which colour of light would be best used to distinguish between two closely spaced specimens?

Tommy Xu