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Author Question: It is desired to project an image of an object four times actual size with a lens of focal length 20 ... (Read 229 times)

fahad

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on: Jul 29, 2018
It is desired to project an image of an object four times actual size with a lens of focal length 20 cm. What object distance should be used?
 
  A)
 
  100 cm
  B)
 
  80 cm
  C)
 
  4 cm
  D)
 
  25 cm
  E)
 
  5 cm

Question 2

Alpha rays can penetrate
 
  A)
 
  air only.
  B)
 
  a piece of paper.
  C)
 
  several millimeters of aluminum.
  D)
 
  several centimeters of lead.
  E)
 
  several meters of iron.


234sdffa

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Reply #1 on: Jul 29, 2018
Answer to Question 1

D

Answer to Question 2

B


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fahad

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Reply #2 on: Jul 29, 2018
TY


234sdffa

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Reply #3 on: Jul 29, 2018
You're welcome


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