HW02solutions

# HW02solutions - 24.40. Model: Assume thin lenses and treat...

This preview shows pages 1–5. Sign up to view the full content.

24.40. Model: Assume thin lenses and treat each as a simple magnifier with 25cm/ . M f = Visualize: Equation 24.10 gives the magnification of a microscope. obj eye obj eye 25cm L MmM f f == Solve: (a) The more powerful lens (4 ) × with the shorter focal length should be used as the objective. (b) Solve the equation above for L (drop the negative sign). 25cm 25cm 42 (12)( )( ) 37.5 cm 25 cm 25 cm obj eye Mf f L = Assess: This is a long microscope tube.

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

View Full Document
24.6. Model: s f W so we can use Equation 24.1: /. mf s = − Solve: 15 mm (2.0 m) 3.0 mm 10 m f hm h h s == −= = The height of the image on the detector is 3.0 mm. Assess: This seems reasonable given typical focal lengths and detector sizes.
24.10. Visualize: We want the same exposure in both cases. The exposure depends on shutter . It Δ We'll also use Equation 24.3. Solve: 2 1 exposure ( -number) t f = Δ∝ Δ 22 11 ( -number) ( -number) tt ff Δ ( -number) (4.0) 1 1 1 s s s ( -number) (5.6) 125 245 250 f f ⎛⎞ Δ= = ⎜⎟ ⎝⎠ Assess: An alternate approach without a lot of calculation is that since we changed the lens (opened) by one f stop that doubles the intensity so we need half the time interval to achieve the same exposure.

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

View Full Document
24.12.
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 11/02/2009 for the course MASTERING PHYS taught by Professor All during the Spring '09 term at Kettering.

### Page1 / 9

HW02solutions - 24.40. Model: Assume thin lenses and treat...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online