# Teenage Pregnancy

Only available on StudyMode
• Published : May 17, 2013

Text Preview
Focal length of convex length
Aim: to investigate how to measure the focal length of a convex lens, by using the lens equation: 1/f=1/u+1/v * Independent variables:
* Screen
* lens
* Dependent variables:
* distance between the source of light and the lens “V” which is “X” value * distance between lens and the screen “ Y value”
* Controlled variables:
* ruler
* screen size
* source of light

* Hypothesis:
When the lens is displaced further away from the light “image” source the focal point is going to get smaller, and when the lens is approached to the light “image” source the focal point should expand wider and moved further away Sketch graph :

* Material and apparatus:
* Plane white screen to see the image to figure out the size of the image * Meter ruler to measure distances
* Method:
1. Place the light source on a surface at the beginning of the meter ruler. 2. Put a white screen at the end of the meter ruler away from the light source. 3. place the convex lens at a spot in between the screen and the light source. 4. Put the cross wire object between the light source and the lens. 5. The image of the cross wire object should appear on the screen’s surface. 6. Measure the distance between the object and the lens “x” 7. Measure the distance between the lens and the white screen “y” 8. Move the lens away or closer to the object and repeat steps 6&8 for 5 times more 9. calculate down the data into a table and make a graph of this experiment.