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प्रश्न
Answer briefly.
Give two uses of radio waves.
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उत्तर
- Radio waves are used for wireless communication purposes.
- They are used for radio broadcasting and transmission of TV signals.
- Cellular phones use radio waves to transmit voice communication in the ultra-high frequency (UHF) band.
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संबंधित प्रश्न
To which part of electromagnetic spectrum does a wave of frequency 3 × 1013 Hz belong?
A wave has a wavelength of 10-3 nm. Name the wave.
State the approximate range of wavelength associated with infrared rays.
Name two electromagnetic waves of frequency smaller than that of violet light. State one use of each.
An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm.name the medium through which it is travelling
How are X-rays produced?
Can a hydrogen atom emit characteristic X-rays?
Moseley's Law for characteristic X-ray is √v = a(Z − b). Here,
50% of the X-ray coming from a Coolidge tube is able to pass through a 0.1 mm thick aluminium foil. The potential difference between the target and the filament is increased. The thickness of the aluminium foil that will allow 50% of the X-ray to pass through will be
The electric current in an X-ray tube (from the target to the filament) operating at 40 kV is 10 mA. Assume that on an average, 1% of the total kinetic energy of the electron hitting hte target are converted into X-rays.
(a) What is the total power emitted as X-rays and (b) how much heat is produced in the target every second?
The Kα and Kβ X-rays of molybdenum have wavelengths 0.71 A and 0.63 A respectively. Find the wavelength of Lα X-ray of molybdenum.
The distance between the cathode (filament) and the target in an X-ray tube is 1.5 m. If the cutoff wavelength is 30 pm, find the electric field between the cathode and the target.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The short-wavelength limit shifts by 26 pm when the operating voltage in an X-ray tube is increased to 1.5 times the original value. What was the original value of the operating voltage?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the scientist who discovered Visible light
Name the scientist who discovered radio waves
Name the scientist who discovered Ultraviolet rays
Name the part of the electromagnetic spectrum which is:
Produced by bombarding a metal target with high electrons.
Define the term "Intensity" in the photon picture of electromagnetic radiation.
Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.
Name the radiation of the electromagnetic spectrum which is used for the following:
Radar and Give the frequency range.
State three properties of infrared radiations similar to that of visible light.
What are the ultraviolet rays?
Answer briefly.
What is a carrier wave?
Solve the numerical problem.
Calculate the frequency in MHz of a radio wave of wavelength 250 m. Remember that the speed of all EM waves in a vacuum is 3.0 × 108 m/s.
Solve the numerical problem.
Calculate the wavelength in nm of an X-ray wave of frequency 2.0 × 1018 Hz.
Solve the numerical problem.
The speed of light is 3 × 108 m/s. Calculate the frequency of red light of a wavelength of 6.5 × 10−7 m.
Which of the following is a tool used for separating the different color wavelengths from each other?
A car is moving towards a high cliff. The car driver sounds a horn of frequency f. The reflected sound heard by the driver has a frequency 2f. If v be the velocity of sound, then the velocity of the car, in the same velocity units, will be:
Find the photon energy in units of ev for electromagnetic wave if waves length 40 m. Given h = 6.63 × 10–34 J.
All components of the electromagnetic spectrum in a vacuum have the same ______
Electromagnetic waves with wavelength
- λ1 is suitable for radar systems used in aircraft navigation.
- λ2 is used to kill germs in water purifiers.
- λ3 is used to improve visibility in runways during fog and mist conditions.
Identify and name the part of the electromagnetic spectrum to which these radiations belong. Also arrange these wavelengths in ascending order of their magnitude.
Identify the part of the electromagnetic spectrum which:
- produces the heating effect.
- is absorbed by the ozone layer in the atmosphere.
- is used for studying crystal structure.
Write any one method of the production of each of the above radiations.
Below is an incomplete table showing the arrangement of electromagnetic spectrum in the increasing order of their wavelength. Complete the table:
| Gamma ray | X - ray | UV rays | Visible rays | Infrared | A | Radio waves |
- Identify the radiation A.
- Name the radiation used to detect fracture in bones.
- Name one property common to both A and Radio waves.
Name one radiation having the wavelength longer than the wavelength of these radiations.
