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JEE Main 2021 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 25 February 2021, Shift 2, Physics Q30

Question 30 of 90 in this shift, Physics question 30 of 30, Section B.

The wavelength of an X-ray beam is 10 Å. The mass of a fictitious particle having the same energy as that of the X-ray photons is

\frac{x}{3}h

kg. The value of

x

is ____________. (h = Planck’s constant)

Official answer

10

NTA final key.

Chapter: Dual Nature of Radiation and Matter
Topic: Matter Waves
Idea tested: Matter Wave vs Photon Energy Scaling

Same idea in other shifts

Asked 2× in all

17 Mar 2021, Shift 1 · Q18An electron of mass m and a photon have same energy E. The ratio of wavelength of electron to that of photon is : (c being the velocity of…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.