Today, I want to introduce you to the 6 methods of testing the focal length of convex lenses, welcome to read!
![What are the 6 ways to test the focal length of a convex lens?](https://cdn.shopifycdn.net/s/files/1/0555/5860/2857/files/What_are_the_6_ways_to_test_the_focal_length_of_a_convex_lens_2.jpg?v=1657245932)
6 ways to test the focal length of a convex lens:
1. Convergence method to make the light collecting seat parallel to the sun, place the light screen and the convex lens on the light collecting seat in turn, fix the light screen (or convex lens), and move the convex lens (or light screen) until the light spot on the light screen is small and bright , the distance between the bright spot and the convex lens is the focal length.
2. Observe the virtual image and place the light screen on the light gathering seat in turn. Convex lens, put a larger copybook on the light screen, and look at the words on the light screen with the convex lens. When the virtual image of the upright magnification of the character appears, the distance between the convex lens and the light screen will gradually increase until the virtual image of the character just disappears, and the distance between the light screen and the convex lens is the focal length.
3. The image, the convex lens and the burning candle are placed on the photocondenser in turn, keep the convex lens still, and move the lit candle and the light screen at the same time, until there is an image of the size of an inverted candle flame on the light screen, then the object distance or image distance half is the focal length.
4. One-shot imaging method Put the light screen, convex lens, burning candle, moving candle and light screen light screen on the light screen until a clear inverted magnified (or reduced) image appears on the light screen, measure the object distance U and the image distance V, substitute into the formula 1/f=1/U+1/V to calculate the focal length.
![What are the 6 ways to test the focal length of a convex lens?](https://cdn.shopifycdn.net/s/files/1/0555/5860/2857/files/What_are_the_6_ways_to_test_the_focal_length_of_a_convex_lens_3.jpg?v=1657245951)
5. The double imaging method places the light screen, the convex lens and the burning candle on the light collecting seat in turn, so that the distance L between the light screen and the candle is greater than 4 times that of the convex lens, so that the distance between the light screen and the candle remains unchanged. Move the convex lens to get a clear candle flame image on the light screen, note the position of the convex lens 1, then move the convex lens to get a clear candle flame image on the light screen, note the position of the convex lens 2.
6. The double-convex lens method makes the optical bench parallel to the sunlight, and places the light screen and two identical convex lenses on the optical bench in turn, so that the sunlight passes through the rectangular hole and shines on the convex lens, changing the distance between the two convex lenses. until the height (or width) of the rectangular spot on the light screen is equal to the height (or width) of the rectangular hole on the cardboard.
Thank you for reading. The above is the introduction of the 6 methods for testing the focal length of convex lenses. If you want to know more about the lens, please contact us and serve you wholeheartedly.