The wavelength of an electron of kinetic energy 4.50 × 10⁻²⁹ J is _____

De Broglie Wavelength of Electron from Kinetic Energy | JEE Main PYQ | Structure of Atom

Q. The wavelength of an electron of kinetic energy 4.50 × 10⁻²⁹ J is ______ × 10⁻⁵ m. (Nearest integer)

Given: mass of electron = 9 × 10⁻³¹ kg, Planck's constant (h) = 6.6 × 10⁻³⁴ J s

Correct Answer: 7

Explanation

De Broglie wavelength of an electron is given by:

λ = h / √(2mK)

Substituting the given values:

h = 6.6 × 10⁻³⁴ J s

m = 9 × 10⁻³¹ kg

K = 4.50 × 10⁻²⁹ J

λ = 6.6 × 10⁻³⁴ / √(2 × 9 × 10⁻³¹ × 4.50 × 10⁻²⁹)

λ ≈ 7 × 10⁻⁵ m

Hence, the required wavelength of the electron is:

7 × 10⁻⁵ m

Previous Year Questions – Structure of Atom