a technician wishes to produce an image on a wall using a thin lens. The lens to
ID: 1269765 • Letter: A
Question
a technician wishes to produce an image on a wall using a thin lens. The lens to wall distance is to be 6 m. He also wants the image to be the same size as the object. What is the focal length of the lens he will need?
2. When does a concave spherical mirror of radius R and a focal length f produce a real image with a size greater than the object which is at distance p?
3. A thin diverging lens produced an image of magnification 1/5 for an object located 20 cm from the lens. what is the focal length of the lens?
Explanation / Answer
1)
Given image distance q = 6 m
object distance p = 6 m.
The thin lens equation is ,
1/ p + 1/q = 1/ f
1/ f = 1/ 6 + 1/ 6
f = 3 m
2)
For an object placed in front of a concave mirror such that the distance of object is greater than the focal length of the lens.The image formed will be real, inverted, and magnified.
3)
Given
object distance p = 20 cm
The magnification of the image is
M = (1/ 5 )p
- q/ p = p / 5
q = - p ^2 / 5
= - (20 cm ) ^2 / 5
=-80 cm
The focal length of the lens is ,
1/f = 1/ p + 1/ q
= 1/ 20 cm + 1/ -80 cm
f =26.6 cm
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.