Question: Q. 6. Name the EM waves which are suitable for radar system used in aircraft navigation. Write the range of frequency of these waves.
R [Delhi I, II, III 2014]
Show Answer
Solution:
Ans. Microwaves ….. $1 / 2$ frequency range $10^{10}$ to $10^{12} \mathrm{~Hz}$. ….. $1 / 2$ [CBSE Marking Scheme 2014]
[A] Q. 7. To which part of the electromagnetic spectrum does a wave of frequency $5 \times 10^{19} \mathrm{~Hz}$ belong ?
R [O.D. I, II, III 2014]
Ans. $X$ rays/Gamma rays.
1
[CBSE Marking Scheme 2014]
Detailed answer :
In electromagnetic spectrum, there is no sharp boundary of frequency among $X$-rays/Gamma rays as frequency range of $X$-rays is $10^{20} \mathrm{~Hz}-10^{16}$ $\mathrm{Hz}$ where as Gamma rays frequency ranges from $10^{22} \mathrm{~Hz}-10^{19} \mathrm{~Hz}$, so waves with frequency $5 \times$ $10^{19} \mathrm{~Hz}$ belongs to both $X$ rays/Gamma rays of electromagnetic spectrum.
1
[A]Q. 8. Arrange the following electromagnetic waves in order of increasing frequency :
R] [Foreign Set I 2014] $\gamma$ rays, microwaves, infrared rays and ultraviolet rays.
Ans. Microwaves < Infrared rays < Ultraviolet rays $<$ $\gamma$-rays.
$10^{13} \mathrm{~Hz}-10^{9} \mathrm{~Hz}<10^{14} \mathrm{~Hz}-10^{12} \mathrm{~Hz}<10^{17} \mathrm{~Hz}$ $-10^{15} \mathrm{~Hz}<10^{22} \mathrm{~Hz}-10^{19} \mathrm{~Hz} \quad 1$
[CBSE Marking Scheme, 2014]
