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प्रश्न
Electromagnetic waves with wavelength
- λ1 is used in satellite communication.
- λ2 is used to kill germs in water purifies.
- λ3 is used to detect leakage of oil in underground pipelines.
- λ4 is used to improve visibility in runways during fog and mist conditions.
- Identify and name the part of electromagnetic spectrum to which these radiations belong.
- Arrange these wavelengths in ascending order of their magnitude.
- Write one more application of each.
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उत्तर
a. (i) In satellite communications, microwave is widely used. Hence λ1, is the wavelength of microwave.
(ii) In water purifier, ultraviolet rays are used to kill germs. So, λ2 is the wavelength of UV rays.
(iii) X-rays are used to detect leakage of oil in underground pipelines. So, λ3 is the wavelength of X-rays.
(iv) Infrared rays are used to improve visibility on runways during fog and mist conditions. So, it is the wavelength of infrared waves.
b. Wavelength of X-rays < wavelength of UV < wavelength of infrared < wavelength of microwave.
⇒ λ3 < λ2 < λ4 < λ1
c.
| Radiation | Uses |
| γ-rays | Gives information on nuclear structure, medical treatment etc. |
| X-rays | Medical diagnosis and treatment study of crystal structure, industrial radiograph. |
| UV-rays | Preserve food, sterilizing the surgical instruments, detecting invisible writings, fingerprints etc. |
| Visible light | To see objects |
| Infrared rays | To treat, muscular strain from taking photography during the fog, haze etc. |
| Microwave and radio wave | In radar and telecommunication. |
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संबंधित प्रश्न
Give the range of wavelength of the electromagnetic waves visible to us.
State the approximate range of wavelength associated with visible light.
Name the waves of wavelength nearly 0.1 nm.
Characteristic X-rays may be used to identify the element from which they are being emitted. Can continuous X-rays be used for this purpose?
Can a hydrogen atom emit characteristic X-rays?
An X-ray beam can be deflected
The energy of a photon of a characteristic X-ray from a Coolidge tube comes from
Cutoff wavelength of X-rays coming from a Coolidge tube depends on the
(a) target material
(b) accelerating voltage
(c) separation between the target and the filament
(d) temperature of the filament.
The X-ray coming from a Coolidge tube has a cutoff wavelength of 80 pm. Find the kinetic energy of the electrons hitting the target.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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 |
Heat at the rate of 200 W is produced in an X-ray tube operating at 20 kV. Find the current in the circuit. Assume that only a small fraction of the kinetic energy of electrons is converted into X-rays.
A certain element emits Kα X-ray of energy 3.69 keV. Use the data from the previous problem to identify the element.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The wavelengths of Kα and Lα X-rays of a material are 21.3 pm and 141 pm respectively. Find the wavelength of Kβ X-ray of the material.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
When 40 kV is applied across an X-ray tube, X-ray is obtained with a maximum frequency of 9.7 × 1018 Hz. Calculate the value of Planck constant from these data.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Give one use of electromagnetic radiation in Microwaves.
Choose the correct option.
The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is
Answer briefly.
What are radio waves?
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.
The speed of light is 3 × 108 m/s. Calculate the frequency of red light of a wavelength of 6.5 × 10−7 m.
Given below in the left column are different modes of communication using the kinds of waves given in the right column.
| A. | Optical Fibre Communication |
P. | Ultrasound |
| B. | Radar | Q. | Infrared Light |
| C. | Sonar | R. | Microwaves |
| D. | Mobile Phones | S. | Radio Waves |
From the options given below, find the most appropriate match between entries in the left and the right column.
