Academic session 2026-27, Chapter 11 in the current curriculum.
Welcome to the NCERT Solutions for Class 12 Physics - Chapter Dual Nature Of Radiation And Matter. This page offers a step-by-step solution to the specific question from Exercise 1, Question 16:
An electron and a photon each have a wavelength of 1.00 nm. Find
(a) their momenta,
(b) the energy of the photon, and
(c) the kinetic energy of electron.
. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.An electron and a photon each have a wavelength of 1.00 nm. Find
(a) their momenta,
(b) the energy of the photon, and
(c) the kinetic energy of electron.
Wavelength of an electron (λe) and a photon (λp), λe = λp = λ = 1 nm = 1 × 10−9 m
Planck’s constant, h = 6.63 × 10−34 Js
(a) The momentum of an elementary particle is given by de Broglie relation: λ = h/p
∴ p = h/λ
It is clear that momentum depends only on the wavelength of the particle. Since the wavelengths of an electron and a photon are equal, both have an equal momentum.
∴ p = 6.63 x 10-34 / 1 x 10-9 = 6.63 x 10-25 kg m s-1
(b) The energy of a photon is given by the relation: E = hc/λ
Where,
Speed of light, c = 3 × 108 m/s
∴ E = 6.63 x 10-34 x 3 x 108 / 1 x 10-9 x 1.6 x 10-19 = 1243.1 eV
Therefore, the energy of the photon is 1.243 keV.
(c) The kinetic energy (K) of an electron having momentum p, is given by the relation: K = 1/2 p2 / m
Where,
m = Mass of the electron = 9.1 × 10−31 kg
p = 6.63 × 10−25 kg m s−1
∴ K = 1/2 x (6.63 x 10-25)2 / 9.1 x 10-31 = 2.415 x 10-19 J
= 2.415 x 10-19 / 1.6 x 10-19 = 1.51 eV
Hence, the kinetic energy of the electron is 1.51 eV.
NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:
Stay updated with our latest educational content and study tips
It’s not about starting over if you took a break to care for children, take care of yourself, be healthy or for any other reason. This is a realistic strategy for the recovery of skills, selection of the right job, and overcoming the resume problem. One year, three years or 10 years of a career … Read more
Read MoreThere’s no need to score 95% or achieve a JEE/NEET rank. You don’t need to score 95% or rank in JEE/NEET to build a solid career. A candid and pragmatic guide to the routes that actually work for students who have an average mark and what to do when faced with the options. If … Read more
Read MoreAI tools, online platforms that are much cheaper than coaching centres and the changing idea of what “structure” even means have upended this argument more in the past two years than in the decade preceding it. Here’s what is really the case for 2026 – and what has actually stayed the same. If you look … Read more
Read MoreStarting to make a new career after 30 isn’t a start from scratch. Marketing, teaching, financial, retail, healthcare, sales and other professionals can pursue careers in technology by applying the existing knowledge and skills they have acquired to new technology skills. There are various ways to enter the technology industry, such as in IT support, … Read more
Read MoreCalculate percentage from obtained marks and total marks.
Welcome to the NCERT Solutions for Class 12 Physics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 16: An electron and a photon each have a wavelength of 1.00 nm. Find (a) their momenta, (b) the en....
Fresh educational articles and updates.
Most-read articles from SaralStudy.
Fast access to frequently used study resources.
Recently viewed articles based on SaralStudy activity.
Add Comment