| ⇦ | 
| ⇨ |
Monochromatic light of wavelength 667 nm is produced by a helium neon laser. The power emitted is 9 mW. The number of photons arriving per second on the average at a large irradiated by this beam is:
Options
(a) 3 x 10¹⁶
(b) 9 x 10¹⁵
(c) 3 x 10¹⁹
(d) 9 x 10¹⁷
Correct Answer:
3 x 10¹⁶
Explanation:
λ = 667 x 10⁻⁹ m, P = 9 x 10⁻³ W
P = Nhc / λ, N = no. of photons emitted/sec.
N = (9 x 10⁻³ x 667 x 10⁻⁹) / (6.6 x 10⁻³⁴ x 3 x 10⁸)
= 9 x 6.67 x 10⁻¹⁰ / 3 x 6.6 x 10⁻²⁶
3 x 10¹⁶ / sec
Related Questions: - An alternating emf given by equation
e=300 sin[(100 π)t] V
- The kinetic energy needed to project a body of mass m from the surface of earth
- If ∆Q>0 when heat flows into a system, ∆W>0 when work is done on the system
- The wave described by y = 0.25 sin (10 2πx – 2πt), where x and y are in meters
- A light emitting diode(LED) has a voltage drop of 2 volt across it
Topics: Dual Nature of Matter and Radiation
(150)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- An alternating emf given by equation e=300 sin[(100 π)t] V
- The kinetic energy needed to project a body of mass m from the surface of earth
- If ∆Q>0 when heat flows into a system, ∆W>0 when work is done on the system
- The wave described by y = 0.25 sin (10 2πx – 2πt), where x and y are in meters
- A light emitting diode(LED) has a voltage drop of 2 volt across it
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
Leave a Reply