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Phy 122
Your 'question form' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** Question Form_labelMessages **
Real or Virtual Image
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Problem set 6 #22 says:
Problem
A person 1.44 meters high stands 3 meters from a converging lens with focal length 50 millimeters.
Where will the image form?
Will the image be upright or inverted?
How large will the image be?
Will it be real or virtual?
Sketch a diagram explaining how the image forms.
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You helped me with this problem before and I think I understand pretty well. I just need to confirm that my thinking is right on the question of whether the image is real or virtual.
I think its real because with this converging lens the image is focused on a point on the far side of the lens (far side in relation to the actual object) and if you had a screen on that far side, you would see the image. This would mean the image is real.
???Am I right in this line of thinking???
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That is correct. The 'rays' really follow those paths, so they would illuminate a screen at that location.
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#$&*
Phy122
Your 'question form' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** Question Form_labelMessages **
Path Difference
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Problem set 6 #21 states:
Two sources separated by 10.04 * 10^-2 meters produce microwaves. The sources are in phase. The waves have wavelength 2.7 * 10^-2 meters are observed at a distance of several meters from the sources. A line from the sources to the point of observation makes an angle of 46.6 degrees with the perpendicular bisector of the line segment joining the sources.
By what fraction of a wavelength will the wave emitted from the source further from the observer lag the wave emitted from the closer source?
What are the first three angles at which the strength of the radiation reaching the observer would be minimized?
What are the first two angles at which the radiation reaching the observer would be maximized?
Solution
At angle 46.6 degrees, the wave from the further of the sources will travel a distance
path difference = 10.04 * 10^-2 meters * sin( 46.6 degrees) = 7.294822 * 10^-2 meters
further than the wave from the closer. This path difference is
number of wavelengths = path diff / wavelength = 7.294822 * 10^-2 meters / 10.04 * 10^-2 meter= `nWavelengths
wavelengths.
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???Would I be right to think the last line is a typo and should read
number of wavelengths = path diff / wavelength = 7.294822 * 10^-2 meters / (2.7 * 10^-2 meters/wavelength)= 2.702 Wavelengths
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That is correct. The randomizer got ahold of the wrong variable (not to deflect blame; actually it looks like I referenced the wrong variable in the programming).
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