Question

A concave and convex lens have the same focal length of 20 cm and are put in contact to form a lens combination. The combination is used to view the object of 5 cm length kept at 20 cm from the combined lens. Then

• A. the image is magnified
• B. the image is inverted
• C. the image is of same size
• D. the image is errect

Answer 1

Answer: (C), (D)

The correct options are
C the image is of same size
D the image is errect

$feq=\frac{f_1{f}_2}{f_1+f_2}=\frac{20\times -20}{0}$
$\Rightarrow$ the lens combination acts as a rectangular slab hence image is of same size is erect