NTA Abhyas JEE Main2020PhysicsDual Nature of MatterPractice
The energy that should be added to an electron to reduce its de-Broglie wavelength from 1 nm to 0.5 nm is
Options
- Afour times the initial energy
- Bequal to the initial energy
- Ctwice the initial energy
- Dthrice the initial energy
Correct answer
D. thrice the initial energy
Step-by-step solution
De-Broglie Wavelength λ = h 2 mE ∴ λ 1 λ 2 = E 2 E 1 ⇒ 1 × 1 0 - 9 0.5 × 1 0 - 9 = E 2 E 1 ⇒ 2 = E 2 E 1 ⇒ E 2 E 1 = 4 ∴ E 2 = 4 E 1 ∴ Energy to be added = E 2 - E 1 = 4 E 1 - E 1 = 3 E 1