In the Figure below a lens of focal length 9 cm is placed between a plane mirror
ID: 1437154 • Letter: I
Question
In the Figure below a lens of focal length 9 cm is placed between a plane mirror and a pin hole. The other side of the pin hole is illuminated by a light source (not shown), so that the light passes through the hole and is then collected by the lens. If the pin hole is at the focal point of the lens, then the light that passes through the lens will be parallel. When the parallel rays hit the plane mirror, the reflected rays will also be parallel, and when they pass through the lens again the rays will be focused at the pin hole. This is called the auto-collimation method for finding the focal length of a lens. For this part, the object is to find the location to place the lens and the pin hole to obtain auto-collimation.
Having trouble with Part B! 22.5cm is not correct. Thanks!!!
where all the lengths are measured from the center of the lens. Note: There are two exercises for this pre-lab. As you complete one exercise or have exhausted all your tries, the next exercise will be displayed since it may depend on the results of the earlier exercise(s). In addition, this significantly reduces the time to process each submission. When you have exhausted all your tries, the computer's answer will be displayed. Exercise 1 Focal Length of a Lens When parallel rays pass through a converging lens, the rays converge at a point called the focal point. The distance between the lens and the focal point is the focal length. This length is a characteristic of the lens and is determined from the radius of curvatures and the refractive index of the lens In the Figure below a lens of focal length 9 cm is placed between a plane mirror and a pin hole. The other side of the pin hole is illuminated by a light source (not shown), so that the light passes through the hole and is then collected by the lens. If the pin hole is at the focal point of the lens, then the light that passes through the lens will be parallel. When the parallel rays hit the plane mirror, the reflected rays will also be parallel, and when they pass through the lens again the rays will be focused at the pin hole. This is called the auto-collimation method for finding the focal length of a lens. For this part, the object is to find the location to place the lens and the pin hole to obtain auto-collimation. Question: Where should the pin hole be placed so that it is at the focal point of the lens? Click on the graph near the scale, then click on the "Submit Answer" button. plane mirror ens pin hole cm 01 2 34 56 7 8 9 10 11 12 15 14 15 16 17 18 1920 21 22 23 24 25 0 1 2 3 45 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 When the pin hole is placed at the focal point of the lens, light from the pin hole travels to the lens. The rays passing through the lens will be parallel. When these rays reflect from a plane mirror, the rays will also be parallel. The lens will then focus the beam back to the pin hole. This is how the focal point of a lens is defined; the point where the parallel rays are focused at is called the focal point and the distance from the lens to the focal point is the focal length e mn nn abov reviaus Ties You are correct. Computer's answer now shown above. VI Your receipt no. is 160-8358 The next part of this exercise examines further the concept of focal length The lens in the last part is used to form the image of the sun. What is the image distance? (Recall that the focal length is 9 cm.) 22.5cm An object is located at the focal point of the lens. The image of the object is located at infinity An object is located at the focal point of the lens. The image of the object is located at Iinfniy Pu Put the object distance equal to the focal length in the lens equation. What is the image distance? What is the mathematical word to describe the value?Explanation / Answer
in your equation both f and o are the same.
Look at your equation: 1/f - 1/f = 1/i
Go ahead and do the left side: 0 = 1/i
So, the object image is located at infinity
You have got pin hole distance o in the first part, put in the values -
1/9 = 1/i + 1/o
Solve for i.