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प्रश्न
A wave has wavelength 50 Å.
- Name the wave.
- State its speed in vacuum.
- State its one use.
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उत्तर
- An electromagnetic wave having a wavelength 50 Å is an X-ray. They have a wavelength in the range of 0.1 Å to 100 Å.
- The speed of an electromagnetic wave (here X-ray) in a vacuum is 3x108 m/s.
- Since, they are stopped by bones, they are used for the detection of fractures in bones, teeth, etc., and for diagnostic purposes such as CAT scans in medical science.
संबंधित प्रश्न
X-ray from a Coolidge tube is incident on a thin aluminium foil. The intensity of the X-ray transmitted by the foil is found to be I0. The heating current is increased to increase the temperature of the filament. The intensity of the X-ray transmitted by the foil will be
(a) zero
(b) < I0
(c) I0
(d) > I0
For harder X-rays,
(a) the wavelength is higher
(b) the intensity is higher
(c) the frequency is higher
(d) the photon energy is higher.
Find the maximum potential difference which may be applied across an X-ray tube with tungsten target without emitting any characteristic K or L X-ray. The energy levels of the tungsten atom with an electron knocked out are as follows.
| Cell containing vacancy | K | L | M |
| Energy in keV | 69.5 | 11.3 | 2.3 |
The Kα X-rays of aluminium (Z = 13) and zinc (Z = 30) have wavelengths 887 pm and 146 pm respectively. Use Moseley's law √v = a(Z − b) to find the wavelengths of the Kα X-ray of iron (Z = 26).
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the part of the electromagnetic spectrum which is:
Produced by bombarding a metal target with high electrons.
Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.
Answer briefly.
Why are microwaves used in radar?
Answer briefly.
What are radio waves?
For television broadcasting, the frequency employed is normally
Radio waves of constant amplitude can be generated with.
