Question: Q. 2. Name the EM waves in the wavelength range $10 \mathrm{~nm}$ to $10^{-3} \mathrm{~nm}$. How are these waves generated ? Write their two uses.
U] [O.D. comptt. I 2017]
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Solution:
Ans. Name of EM wave $X$-rays
Produced by bombarding a metal target with high energy electrons.
Uses :
(i) Used in diagnosis of bone fractures.
(ii) Treatment of some forms of cancer.
[CBSE Marking Scheme 2017]
Detailed Answer :
(i) $X$-rays : wavelength $10^{-12} \mathrm{~m}-10^{-8} \mathrm{~m}$, frequency $10^{20}$ $\mathrm{Hz}-10^{16} \mathrm{~Hz}$
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(ii) Generation :
$X$-radiation occurs due to electron transitions among upper and lower energy levels of heavy elements excited by electron bombardment or rapid deceleration of electrons.
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(iii) Uses :
(a) Used in medicine and dentistry $1 / 2$
(b) Mammograms use $X$-rays to identify breast cancer.
