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~11 : 9 : Please help me answer this question. Item 9 A lighted candle is placed

ID: 1386670 • Letter: #

Question

~11 : 9 : Please help me answer this question.

Item 9 A lighted candle is placed 36 cm in front of a converging lens of focal length fi 13 cm, which in turn is 56 cm in front of another converging lens of focal length fo cm. (Figure 1) Figure 1 V of 1 13 cm f2 16 cm H- 36 cm 56 cm Part A Calculate the position of the final image. Express your answer to two significant figures and include the appropriate units. di 20 beyond the second cm lens Submit My Answers Give Up Incorrect, Try Again, 9 attempts remaining Part B Calculate the relative s of the final image Express your answer using two significant figures. 28.8 Submit My Answers Give Up Incorrect, Try Again, 9 attempts remaining Provide Feedback Continue

Explanation / Answer

Note that      
      
1/f = 1/do + 1/di      
      
where      
      
f = focal length =    13   cm
do = object distance =    36   cm
di = image distance      
      
Thus, solving for di,      
      
di =    20.34782609   cm
      
Thus, the magnification, m = -di/do,      
      
m =    -0.565217391  

Thus, for the second lens,

Note that      
      
1/f = 1/do + 1/di      
      
where      
      
f = focal length =    16   cm
do = object distance =    35.65217   cm
di = image distance      
      
Thus, solving for di,      
      
di =    29.0266   cm   [ANSWER, PART A]
      
Thus, the magnification, m = -di/do,      
      
m =    -0.814159454

Thus,

mtot = m1 m2 = -0.5652 * -0.81415

= 0.4602   [ANSWER, PART B]