11 : 7 : Please help me answer this question: Part A A 115-mm -focal-length lens

Question

11 : 7 : Please help me answer this question:

Part A A 115-mm -focal-length lens is used to focus an rage on the sensor of a camera The maximum distance allowed between the lens and the sensor plane is 139mm. How far ahead of the sensor should the lens be if the object to be photographed is 10.0m away? Part B How far ahead of the sensor should the lens be if the object to be photographed is 3.0m away? Part C How far ahead of the sensor should the lens be if the object to be photographed is 1.2m away? Part D What is the closest object this lens could photograph sharply?

Explanation / Answer

a)

u = 10 m

f = 115 mm = 0.115 m

Using the equation.

1/u + 1/v= 1/f

So, 1/10 + 1/v = 1/0.115

So, v = 0.1163 m = 116.3 mm <-------answer

b)

Now, u = 3m

So,

1/3 + 1/v = 1/0.115

So, v = 119.6 mm <--------answer

c)

Now, u = 1.2 m

So, 1/1.2 + 1/v = 1/0.115

So, v = 127.2 mm <-----------answer

d)

Now, for this part,

v = 139 mm

So, 1/u + 1/0.139 = 1/0.115

So, u = 666 mm <-------answer

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.