Exams › JEE Main › Chemistry
In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainly with which the position of the electron can be located is (h = 6.6 × 10^−34 kg m² s^−1, mass of electron, m = 9.1 × 10^−31 kg)
- 5.10 × 10^−3 m
- 1.92 × 10^−3 m
- 3.84 × 10^−3 m
- 1.52 × 10^−4 m
Correct answer: 1.92 × 10^−3 m
Solution
Delta_v = 600 x 0.005/100 = 0.03 m/s, so Delta_p = 9.1e-31 x 0.03 = 2.73e-32. Delta_x >= h/(4*pi*Delta_p) = 6.6e-34/(4*pi*2.73e-32) = 1.92e-3 m.
Related JEE Main Chemistry questions
- At what wavenumber does the first line of the hydrogen Balmer series occur in the atomic spectrum?
- In the hydrogen emission spectrum, a spectral series has its limit at 12186.3 cm⁻¹. This series is identified as
- Two rapidly moving particles X and Y have de Broglie wavelengths of 1 nm and 4 nm, respectively. If the mass of X is nine times the mass of Y, what is the ratio of their kinetic energies, X: Y?
- Given that Planck’s constant is 6.63 × 10⁻³⁴ J s and the speed of light is 3.0 × 10⁸ m s⁻¹, which of the following is nearest to the wavelength, in nanometres, of light having frequency 8 × 10¹⁵ s⁻¹?
- A lithium ion and a proton are each accelerated through the same potential difference. If their de Broglie wavelengths are λ₁ and λ₂, respectively, and m_(Li) = 9mₚ, what is the ratio λ₁: λ₂?
- The ionisation energy of He⁺ is 19.6 × 10⁻¹⁸ J atom⁻¹. What is the energy of the first stationary state (n = 1) of Li²⁺?
⚔️ Practice JEE Main Chemistry free + battle 1v1 →