Given:
f = -20 cm
height, h = 25 cm
distance = 50 cm
Let's find the size and position of the birds image.
Apply the formula:
[tex]\frac{1}{f}=\frac{1}{v}+\frac{1}{u}[/tex]
Where:
f = -20 cm
u = - 50 cm
Rewrite the formula and solve for v.
[tex]\begin{gathered} \frac{1}{v}=\frac{1}{f}-\frac{1}{u} \\ \\ \frac{1}{v}=\frac{1}{20}-\frac{1}{-50} \\ \\ \frac{1}{v}=\frac{1}{20}+\frac{1}{50} \\ \\ \frac{1}{v}=\frac{5+2}{100} \\ \\ \frac{1}{v}=\frac{7}{100} \\ \\ v=\frac{100}{7}=14.28\text{ m/s} \end{gathered}[/tex]
Now, let's find the height of the image:
[tex]\begin{gathered} \frac{h_i}{h_o}=\frac{-v}{u} \\ \\ \frac{hi}{25}=\frac{-14.28}{-50} \\ \\ hi=\frac{14.28*25}{50} \\ \\ h_i=7.14\text{ cm} \end{gathered}[/tex]
We can see the image height is smaller.
The formed image is virtual and erect.
ANSWER:
• The image height is smaller.
,
• The formed image is virtual and erect.