Kaitlynne is using a magnifying glass (f = 0.098 m)while trying to solder a computer circuit board.The image is 0.21 m from the lens.What is the distance between the glass and the circuit board?
A)0.052 m
B)0.062 m
C)0.067 m
D)0.093 m
E)0.16 m

Question

Quizplus · Accepted Answer

Using the thin lens equation: 
1/f = 1/dO + 1/dI 
where f is the focal length, dO is the object distance, and dI is the image distance. 
Rearranging and plugging in the given values: 
1/dO = 1/f - 1/dI 
1/dO = 1/0.098 - 1/0.21 
1/dO = 10.2041 
dO = 0.098 m / 10.2041 
dO = 0.0096 m 
Finally, the distance between the glass and the circuit board is the sum of the object distance and the focal length: 
distance = dO + f 
distance = 0.0096 m + 0.098 m 
distance = 0.067 m
Therefore, the best choice is C.

Kaitlynne Is Using a Magnifying Glass (F = 0