{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

05prob

# 05prob - Physics 9B-C Assignment#5 Cole c 3 108 m = =10-12...

This preview shows pages 1–2. Sign up to view the full content.

Physics 9B-C Assignment #5 Cole [Q35.6] The wavelength for gamma rays is λ == × × c f 31 0 8 m 0 H z 20 =10 -12 m. (see p. 1157). Interference pattern will only be noticable if the distance between the sources í 100 ¬ - 1000 ¬ which means the distance between the sources would have to be about 1 - 10 Å or about the diameter of an atom! For example, see the calculation for y 3 = 1.4 ª 10 -8 m using d = 0.2 mm (p. 1157, example 37-11). The spacing between the interference maxima is too small to see. [Q35.14] The interference process must be coherent. The way thin films achieve cohenence is to reflect part of a wave train of the first surface and another part off the nearby second surface. Because both came from the same wave train, they will have a well-defined phase relation and will interfere coherently. But how long, L, is a typical wave train? If 2 t > L then the first wave will have left before the second one can meet up with it. An atom takes about 10 s to emit a wavetrain õ L = c( 10 s) = 3 ª 10 -4 m = 0.3 mm. If the film thickess is greater than about a tenth of a millimeter, the coherence is lost and the interference pattern washes out. [P35.10] φ π = 2 dy L = 20(2π) õ d L y × () × 20 20 502 10 1 2 9 m m 10.6 10 m -3 .

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 3

05prob - Physics 9B-C Assignment#5 Cole c 3 108 m = =10-12...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online