A. 15.0
B. 2.5
C. 1.5
D. 0.4
Correct Answer:
Option B – 2.5
Explanation
Form the lens formula =Â 1/UÂ +Â 1/VÂ =Â 1/f
=>Â 1/10Â +Â 1/25Â =Â 1/f;
∴ (5 + 2) / 50 = 1/f
∴ f = 50/7cm
since the image is observed on a screen, it is a real image. Thus magnification
M =Â f/U-f
= | __50/7 |
10 –Â 50/7 |
∴ M = | 50/7 |
20/7 |
= 50/7 x 7/20 = 2.5