J & K CET Engineering J and K - CET Engineering Solved Paper-2005

  • question_answer
    An electromagnetic radiation has an energy \[14.4\text{ }eV\]. To which region of electromagnetic spectrum does it belong?

    A)  Ultraviolet region

    B)  Visible region

    C)  X-ray region

    D)  y-ray region

    Correct Answer: A

    Solution :

    From Planck's law, the energy is \[E=hv\] where v is frequency and h the Planck's constant. Also, \[1\,eV=1.6\times {{10}^{-19}}J\] \[\therefore \] \[v=\frac{E}{h}=\frac{14.4\times 1.6\times {{10}^{-19}}}{6.6\times {{10}^{-34}}}\] \[=3.4\times {{10}^{15}}Hz\] The range of frequency of ultraviolet rays varies from \[5\times {{10}^{7}}\text{ }Hz\]to\[7\times {{10}^{14}}\text{ }Hz\]. Hence, the given region belongs to ultraviolet region of electromagnetic spectrum.


You need to login to perform this action.
You will be redirected in 3 sec spinner