Question:

Assuming $f$ to be the frequency of first line in Balmer series, the frequency of the immediate next (i.e. second) line is Assuming $f$ to be the frequency of first line in Balmer series, the frequency of the immediate next (i.e. second) line is

Updated On: Apr 26, 2024
  • 0.50 f
  • 1.35 f
  • 2.05 f
  • 2.70 f
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The Correct Option is B

Solution and Explanation

Balmer series is the series in which the spectral lines correspond to the transition of electron from some higher energy state to the lower energy state corresponding to $n_{f}=2$. Therefore, for Balmer series, $n_{f}=2$ and $n_{i}=3,4,5, \ldots$
Frequency, of 1 st spectral line of Balmer
series $f=R Z^{2} c\left(\frac{1}{2^{2}}-\frac{1}{3^{2}}\right)$
Or $f=R Z^{2} c \times \frac{5}{36} ....$(i)
Frequency of 2 nd spectral line of Balmer series
$f^{\prime}=R Z^{2} c\left(\frac{1}{2^{2}}-\frac{1}{4^{2}}\right)$
or $f^{\prime}=R Z^{2} c \times \frac{3}{16} ....$(ii)
From Eqs. (i) and (ii), we have
$\frac{f}{f^{\prime}}=\frac{20}{27}$
$\therefore f^{\prime}=\frac{27}{20} f=1.35 f$
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Concepts Used:

Atoms

  • The smallest unit of matter indivisible by chemical means is known as an atom.
  • The fundamental building block of a chemical element.
  • The smallest possible unit of an element that still has all the chemical properties of that element.
  • An atom is consisting of a nucleus surrounded by one or more shells of electrons.
  • Word origin: from the Greek word atomos, which means uncuttable, something that cannot be divided further.

All matter we encounter in everyday life consists of smallest units called atoms – the air we breath consists of a wildly careening crowd of little groups of atoms, my computer’s keyboard of a tangle of atom chains, the metal surface it rests on is a crystal lattice of atoms. All the variety of matter consists of less than hundred species of atoms (in other words: less than a hundred different chemical elements).

Atom
Atom

 

 

 

 

 

 

 

 

Every atom consists of an nucleus surrounded by a cloud of electrons. Nearly all of the atom’s mass is concentrated in its nucleus, while the structure of the electron cloud determines how the atom can bind to other atoms (in other words: its chemical properties). Every chemical element can be defined via a characteristic number of protons in its nucleus. Atoms that have lost some of their usual number of electrons are called ions. Atoms are extremely small (typical diameters are in the region of tenths of a billionth of a metre = 10-10 metres), and to describe their properties and behaviour, one has to resort to quantum theory.