Convex Lens Focal Length

Materials Required

  • Thin convex lens
  • a lens holder
  • a screen fixed to a stand
  • meter scale

 

The Procedure

Real Lab Procedure

  • Place a thin convex lens vertically on a lens holder kept on a table. The lens should face a distant object outside the window (a tree or an electricity pole or a distant building).
  • Place a screen fixed on a stand on the other side of the lens. Move the screen back and forth to obtain a sharp, clear and inverted image of the distant object.
  • Measure the distance between the screen and the optical centre of the convex lens using a measuring scale. Record the observation as the focal length of the lens.
  • Repeat the experiment at least 3 times and record it in the observation table.
  • Find the mean value of focal length.

 

Observations

Sl No Name of the distant object Distance between the convex lens and the screen (f) Mean focal length of the convex lens, f
1    
2    
3    

 

Result

The focal length of the given convex lens is _________.