Activity 1 Determine the Focal Distance of a Concave Mirror

You will determine the focal distance of a spherical mirror in two different ways and compare your results (they should be equal if everything is correct).

Setup 1 Parallel beam will go through the focus of a mirror

Select a Circular Arc from the Mirrors menu and set up a spherical mirror on the screen.

Select a beam of rays and let them be parallel to the mirror’s main axis. They will be reflected through one point, the focus.

Using the ruler, measure the focal distance (in pixels) from the mirror to where the beam is reflected in the focus.

Note. Remember to save your pictures (screenshots) for your lab submission!

Setup 2 The Mirror Equation

We’ll use the mirror equation to determine f here

Reset the simulation (clear up screen).

Select a circular arc from the mirror menu and create a concave spherical mirror out of it.

Select a point source from the simulation and place it on the screen in front of a spherical mirror. The rays emerging from the object will eventually cross at another point after reflection – that is the location of the image.

Using the ruler, determine and

Using the Mirror equation, calculate the focal distance .

Results

Are the values from Setup1 and Setup2 equal to each other?

____________

____________

Percent Difference:

_______________

Activity 2The Focal Distance of a Converging Lens

The Lens equation has an identical form as the Mirror Equation. The difference here is that the negative distances are those that appear in front of the lens and not behind.

Reset to clear up the simulation and select an ideal lens from the Glass menu.

Move the focal distance slider left and right to set up the focal distance to be 200 pixels.

Select a point source and place it a distance from the lens. The rays from the point source will refract through the lens and intersect again at the image location.

Use the ruler to determine  and

Calculate the focal distance using the equation and compare it with the 200 that you set up in the beginning of the activity.

Results

Are the values from Setup1 and Setup2 equal to each other?

____________

__200_________

Percent Difference:

_______________

Activity 3 Focal Distance of Diverging Lens

Clear up the simulation and set up an ideal lens from the glass menu. Move the lens focal distance slider to -200. Now you have a diverging lens.

Place a point source in front of the lens and measure  and  with the ruler.

Use the mirror equation to determine .

Remember to use the value of  as a negative number because the image is on the “wrong” side of the lens.