Verified Solution • 2025–26 Session moderate

QJEEM24Cha135: JEE Main 2024 Chemistry - Class 11 JEEM24Cha135 Solution: Wavenumber for a radiation having 5800 wavelength is The value…

Wavenumber for a radiation having 5800 Ao\mathop A\limits^o wavelength is x×10 cm−1x \times 10 \mathrm{~cm}^{-1} The value of xx is ________. (Integer answer)

Step-by-Step Verified Solution

The wavenumber of a radiation is defined as the number of wavelengths per unit distance and is the reciprocal of the wavelength. Wavenumber is commonly represented in units of cm−1\mathrm{cm}^{-1} .

First, convert the given wavelength from angstroms ( Ao\mathop A\limits^o ) to centimeters (cm). We know that:

1Ao=10−8 cm1 \mathop A\limits^o = 10^{-8} \, \text{cm}

Given wavelength is 5800 Ao\mathop A\limits^o :

5800Ao=5800×10−8 cm5800 \mathop A\limits^o = 5800 \times 10^{-8} \, \text{cm}

Now calculate the wavenumber ( ν~\tilde{\nu} ) which is the reciprocal of the wavelength:

ν~=15800×10−8 cm\tilde{\nu} = \frac{1}{{5800 \times 10^{-8} \, \text{cm}}}

Simplify the expression:

ν~=15800×10−8 cm=1085800 cm−1\tilde{\nu} = \frac{1}{5800 \times 10^{-8} \, \text{cm}} = \frac{10^8}{5800} \, \mathrm{cm}^{-1}

Now, divide the numerator by the denominator to calculate the precise value:

ν~=1085800≈1.724×104 cm−1\tilde{\nu} = \frac{10^8}{5800} \approx 1.724 \times 10^4 \, \mathrm{cm}^{-1}

Here, it is given that the wavenumber is in the form of x×10 cm−1x \times 10 \, \mathrm{cm}^{-1} , so xx would be the value we calculated divided by 10:

x=1.724×10410=1724x = \frac{1.724 \times 10^4}{10} = 1724

Thus, the integer answer for the value of xx is:

1724

Related Learning Resources & Exam Preparation