Question

Two convex lenses have focal lengths $10$cm and $40$cm. If a telescope has to be made by using these two lenses
$1$. The distance between the lenses should be $50$cm
$2$. The distance between the lenses should be $30$cm
$3$. The magnifying power of this telescope will be $5$
$4$. An inverted image will be produced in this telescope
Which two of the give are correct?

• A. $1$ and $4$
• B. $2$ and $4$
• C. $1$ and $3$
• D. $3$ and $4$

Answer 1

Answer: (A)

$1$ and $4$

Length of telescope tube = $f_1+f_2$

$=10+40$

$=50cm$

Inverted Image is formed in telescope