Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
122 views
in Physics by (114k points)
closed by

What will be momentum of a photon of wavelength 1000 Å? given h = 6.626 × 10-34 Js


1.

6.626 × 10-27 Kg-m/s


2.

6.626 × 10-31 Kg-m/s


3.

3.2 × 10-34  Kg-m/s


4.

None of the above

1 Answer

0 votes
by (115k points)
selected by
 
Best answer
Correct Answer - Option 1 :

6.626 × 10-27 Kg-m/s


CONCEPT:

  • Photon: The photon is an elementary particle. It is a basic unit of light. 
    • Photons are massless, and they always move at the speed of light in a vacuum ( c = 3 × 108  m/s)
  • The momentum of a photon: It is given by Planck's constant divided by the wavelength of the light.

\(P=\frac{h}{λ}\)

where P is the momentum of one photon, h is the Planck constant, and λ is the photon's wavelength. In this equation h is constants.

CALCULATION:

Given that: λ = 1000 Å = 1000 × 10-10 m

h = 6.626 × 10-34  (constant)

c =  3 × 108   (constant)

 p = h / λ 

⇒ p = 6.626 × 10-34 / 1000 × 10-10

⇒ p = 6.626 × 10-27 Kg-m/s

The correct answer is Option 1 i.e 6.626 × 10-27 Kg-m/s

  • Despite photons having no mass, Photon particles carry momentum as well as energy.
    • There has been evidence that EM radiation carries momentum. (Maxwell and others who studied electromagnetic waves have predicted that these carry momentum.) 
  • It is now a well-established fact that photons do have momentum and energy.

  • Photon energy is the energy that is carried by a single photon. The amount of this energy is inversely proportional to the wavelength.

Related questions

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...