What isfocal lengthof lens

It is also possible to draw a graph, on graph paper, of 1/v (y-axis) against 1/u. The equation of the line can be compared to the standard form of linear equation, y = mx + c. In this case it is: 1/v = -1/u + 1/f. This cuts (intercepts) the y-axis (1/v axis) when x (1/u) is zero i.e. 1/v = 0 + 1/f. Similarly the line intercepts the 1/u axis when 1/v is zero, giving us 1/u = 1/f. From your graph get the average of the two intercepts, find the reciprocal to get the value of f.

In the 90's, Red Laser Pointers were the first handheld laser pointer to enter the market. A red laser pointer is perfect for indoor use, presentations, aligning things and playing with pets.

Formula focal lengthcalculator

- Laser Colour: Red - Laser Wavelength: 650nm - Output Power: 5mW - Beam Diameter: Straight - Voltage: 3V - Switch: Push Button - Batteries: 2 AAA (included)

When a ray box is placed on one side of a converging (convex) lens and a screen is placed on the other side, a real image of the object (slit at front of ray box) can be formed on the screen. The ray box is moved and the image located on the screen. The object distance (u) and image distance (v) are measured. The focal length (f) can then be calculated using the formula: 1/f = 1/u + 1/v. Note 1: In this simulation a focal length (between 15 and 35 cm) is set initially and you need to calculate its value. Note 2: If the ray box is inside the focal point you do not get a real image. It is virtual and in front of the lens.

Canada allows handheld laser pointers up to 5mW only. Handheld laser pointers above 5mW are not allowed to be sold, according to Health Canada.