When an object is placed 40cm from a diverging lens, its virtual image is formed 20 cm

⇦

⇨

When an object is placed 40cm from a diverging lens, its virtual image is formed 20 cm from the lens. The focal length and power of lens are

Options

(a) F=-20 cm, P=-5 D
(b) F=-40 cm, P=-5 D
(c) F=-40 cm, P=-2.5 D
(d) F=-20 cm, P=-2.5 D

Correct Answer:

F=-40 cm, P=-2.5 D

Explanation:

We have, 1 / f = (1/v) – (1/u) ⇒ 1 / f = (1/-20) – (-1/40) = (-1 + 1) / 40 = 1 / 40

f = – 40 cm

Power of the lens, P = – (200 / 0.40) = – 2.5 D

Related Questions:

1. An air core coil and an electric bulb are connected in series with an AC source.
2. Graph of force per unit length between two long parallel current carrying
3. A mass m moving horizontally (along the x-axis) with velocity v collides and sticks
4. A charge of 40 µC is given to a capacitor having capacitance C=10 µF
5. The temperature coefficient of resistance of an alloy used for making resistor is

Topics: Ray Optics (94)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends