The number of photons of wavelength of 540 nm emitted per second by an electric bulb

⇦

⇨

The number of photons of wavelength of 540 nm emitted per second by an electric bulb of power 100 W is (given h=6×10⁻³⁴ J-s)

Options

(a) 100
(b) 1000
(c) 3×10²⁰
(d) 3×10¹⁸

Correct Answer:

3×10²⁰

Explanation:

Power = nhc / ( × t)

⇒ 100 = [n × (6 × 10⁻³⁴) × (3 × 10⁸)] / (540 × 10⁹ × 1)

⇒ n × 18 × 10⁻²⁶ / 540 × 10⁻⁹ = 100

⇒ n = 100 × 540 × 10⁻⁹ / 18 × 10⁻²⁶ = 3 x 10²⁰

Related Questions:

1. The unit of thermal conductivity is
2. The radius of a planet is twice the radius of earth. Both have almost
3. Before using the tangent galvanometer, its coil is set in
4. The interferance pattern is obtained with two coherent light sources of intensity
5. The unit of surface tension is

Topics: Dual Nature of Matter and Radiation (150)
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