A convex lens of focal length 25 cm is placed at a distance x from a concave lens of focal length 7 cm. When a parallel beam is incident on the convex lens, it emerges as a parallel beam out of the concave lens. The value of x is

Question

A convex lens of focal length 25 cm is placed at a distance x from a concave lens of focal length 7 cm. When a parallel beam is incident on the convex lens, it emerges as a parallel beam out of the concave lens. The value of x is (A) 20 cm (B) 18 cm (C) 16 cm (D) 14 cm

Tardigrade Admin · Accepted Answer

Here f2=x+f1 When x=f2-f1=18 cm

Q. A convex lens of focal length 25 cm is placed at a distance x from a concave lens of focal length 7 cm. When a parallel beam is incident on the convex lens, it emerges as a parallel beam out of the concave lens. The value of x is

20 cm

18 cm

16 cm

14 cm

Here $f_{2} = x + f_{1}$
$Wh e n x = f_{2} - f_{1} = 18 c m$

Q. A convex lens of focal length 25 cm is placed at a distance x from a concave lens of focal length 7 cm. When a parallel beam is incident on the convex lens, it emerges as a parallel beam out of the concave lens. The value of x is

20 cm

18 cm

16 cm

14 cm

Here f2​=x+f1​ Whenx=f2​−f1​=18cm

Here $f_{2} = x + f_{1}$
$Wh e n x = f_{2} - f_{1} = 18 c m$