An object 8 cm tall is in front of a concave mirror. Linear magnification is −2. Find image height.

Solution & explanation

1. Given h₀ = +8 cm and M = −2.

2. Write signed linear magnification.

   $$M=\frac{h_i}{h_0}$$

3. Multiply by object height.

   $$h_i=M\times h_0$$

4. Insert values with signs.

   $$h_i=-2\times 8$$

5. Multiply.

   $$h_i=-16$$

6. Negative height means inverted; its size is 16 cm.

hᵢ = −16 cm: inverted, twice the object height