Related Problems with Solution
Problem 3 : A converging lens with a focal length of 15 cm forms a real image 30 cm from the lens. Calculate the object distance and the height of the object if the image is twice the size of the object.
Solution :
Use the lens formula: 1/f = 1/v - 1/u
- f = focal length of the lens = 15 cm
- v = image distance = 30 cm
- Let h be the height of the object and 2h be the height of the image.
Plugging these values into the formula: 1/15 = 1/30 - 1/u
Now, solve for u: 1/u = 1/30 - 1/15 1/u = (2 - 1)/30 1/u = 1/30
u = 30 cm
Now that we have the object distance (u), we can calculate the height of the object (h) using the magnification formula: Magnification (M) = -v/u = (2h)/h -30/30 = 2h/h Solve for h: -1 = 2
