Experiment 9: Concave and Convex Mirror

Purpose:
The purpose of this experiment is to study the properties of the concave and convex mirror. Students will examine the mirrors by placing the object in front of the mirrors in different distances and observing the images in the mirrors.
Procedure:
1. Obtain a convex mirror, concave mirror, object which is a marker, ruler.

2. Experiencing the convex mirror:

A.  Place the marker in front of the convex mirror and describe the image characteristics:

- The image appears smaller than the object.
-The image is upright.
-The image is located behind the mirror.
B.  When moving the object closer to the mirror, the image is getting bigger. Once the object is close the mirror, the image is as same size as the object.

C.  When moving the object further from the mirror, the image is getting smaller.
D. Measure the distances and the heights of the object and the image.

d₀ = 50±2 cm

h₀= 12±1 cm

h_i = 4±1cm

d_i/h_i = d₀/h₀  → d_i = d₀h_i/h₀ = 50*4/12 = 16.67 cm

E. Calculate the magnification:

m= h_i/h₀ = 4/12 = 0.333

F. Sketch the image using the light ray diagram.

Yes, our observations agreed with the light ray sketch.

3. Experiencing the concave mirror:

A. Place the object in front of the mirror and describe the image characteristics:

- The image appears larger than the object.

- The image is inverted.

- The image is located between the mirror and the object.

B. When moving the object closer to the mirror, the image is getting bigger. At one point, the image appears upward behind the mirror and is smaller than the object.Once the object is close to the image is as same size as the object.

C.When moving the object further from the mirror, the image is getting smaller.

D. Measure the distances and the heights of the object and the image.

d₀ = 1000±2 cm

h₀= 12±1 cm

h_i =16.5±1cm

d_i/h_i = d₀/h₀  → d_i = d₀h_i/h₀ =100*16.5/12 = 137.5 cm

E. Calculate the magnification:

m= h_i/h₀ = 16.5/12 = 1.375

F. Sketch the image using the light ray diagram.

No, our observations did not agree with the light ray sketch. The image which we observed is bigger than the object. The reason is that we might place the object a distance closer than radius of the mirror.

Summary:

For the convex mirror, we always get the image is virtual and upright, and smaller than the object. As moving closer the the mirror, the image is getting bigger.

For the concave mirror, we can have the image is virtual or real, upright or inverted depending on where we place the object.