COMPASSLearning
RegisterLogin

JEE Main · 2021 · 26 Aug 2021 · Shift 1 · Atomic Structure

WhatsApp Email
Given below are two statements.
Statement I: According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increases with decrease in positive charges on the nucleus as there is no strong hold on the electron by the nucleus.
Statement II: According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increases with decrease in principal quantum number.
In the light of the above statements, choose the most appropriate answer from the options given below:
  1. (A)Statement I is false but Statement II is true✓ Correct
  2. (B)Statement I is true but Statement II is false
  3. (C)Both Statement I and Statement II are true
  4. (D)Both Statement I and Statement II are false

Answer: (A)

Solution

In Bohr's model the speed of the electron in the th orbit is

The speed is proportional to the nuclear charge, so reducing the positive charge on the nucleus lowers the speed rather than raising it, and Statement I is false. The same expression makes the speed inversely proportional to the principal quantum number, so the speed rises as falls, and Statement II is true. Statement I is false but Statement II is true.

JEE Main · 2021 · 26 Aug 2021 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Atomic Structure →

More JEE Main questions on Atomic Structure

  1. Given below are two statements:

    Statement I: When an electric discharge is passed through gaseous hydrogen, the hydrogen molecules dissociate and the energetically excited hydrogen atoms produce electromagnetic radiation of discrete frequencies.

    Statement II: The frequency of s …
    JEE Main 2026View solution →
  2. The energy required by electrons, present in the first Bohr orbit of hydrogen atom to be excited to second Bohr orbit is ____ .

    Given : .
    JEE Main 2026View solution →
  3. Consider the following spectral lines for atomic hydrogen:
    A. First line of Paschen series
    B. Second line of Balmer series
    C. Third line of Paschen series
    D. Fourth line of Bracket series

    The correct arrangement of the above lines in ascending order of energy is:
    JEE Main 2026View solution →
  4. The energy of first (lowest) Balmer line of H atom is x J. The energy (in J) of second Balmer line of H atom is :
    JEE Main 2026View solution →
  5. Which of the following statements regarding the energy of the stationary state is true in the following one-electron system ?
    JEE Main 2026View solution →
  6. Given,
    (A)
    (B)

    The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) respectively are :
    JEE Main 2026View solution →