Description : Explain ionospheric propagation with neat sketch. Explain two properties of layers of ionosphere.
Last Answer : Diagram : Explanation: The transmitted signal travels into the upper atmosphere where it is reflected back to earth due to the presence of layers called as ionosphere in the upper ... having highest electron density of all layers, due to this F2 layer remains present at night time.
Description : . What causes ionization to occur in the ionosphere?
Last Answer : High energy ultraviolet light waves from the sun.
Description : What three main factors determine the amount of refraction in the ionosphere?
Last Answer : (a) density of ionization of the layer (b) frequency (c) angle at which it enters the layer
Description : What are the three more common types of irregular variations in the ionosphere?
Last Answer : Sporadic E, sudden disturbances, and ionospheric storms.
Description : What are the four main classes of regular variation which affect the extent of ionization in the ionosphere?
Last Answer : Daily, seasonal, 11-year, and 27-days variation
Description : What are the two general types of variations in the ionosphere?
Last Answer : Regular and irregular variations.
Description : What factor determines whether a radio wave is reflected or refracted by the ionosphere?
Last Answer : Thickness of ionized layer.
Description : What is the height of the individual layers of the ionosphere?
Last Answer : D layer is 30-55 miles, E layer 55-90 miles, and F layers are 90- 240 miles.
Description : How are the four distinct layers of the ionosphere designated?
Last Answer : D, E, F1, and F2 layers.
Description : The angle of elevation of the antenna beam is 20°. Calculate the transmission-path distance for an ionospheric transmission that utilizes a layer of virtual height 200 km. Use flat-earth approximation. A. 966 km B. 2100 km C. 1100 km D. 405 km
Last Answer : C. 1100 km
Description : What ionospheric layer has a daytime approximate critical frequency of 8 MHz? A. F2 layer B. F1 layer C. E layer D. D layer
Last Answer : A. F2 layer
Description : What height of an ionized layer is determined from the time interval between the transmitted signal and the ionospheric echo at vertical incidence? A. Virtual height B. Apparent height C. Actual height D. Effective height
Last Answer : A. Virtual height
Description : What is the refractive index of an ionospheric layer with 100x105 free electrons per m3 ? Assume frequency to be at 20 MHz. A. 0.99 B. 0.15 C. 0.78 D. 0.85
Last Answer : A. 0.99
Description : This type of transmission permits communication in the frequency range from 30 to 60 MHz and over distances from about 1000 to 2000 km. A. Troposcatter B. Ionospheric scatter C. Ducting D. Microwave
Last Answer : B. Ionospheric scatter
Description : Type of transmission path that permits communication in the frequency range from 30 to 60 MHz and over distances form about 1000 to 2000 km. A. Ducting B. Ionospheric scatter C. Microwave D. Troposcatter
Description : Helical antennas are oftenused forsatellite trackingatVHFbecauseof a. troposcatter b. superrefraction c. ionospheric refraction d.theFaradayeffect
Last Answer : d.theFaradayeffect
Description : Whenmicrowave signalsfollowthe curvatureofthe earth,thisisknownas a. the Faraday effect b.ducting c. tropospheric scatter d. ionospheric reflection
Last Answer : b.ducting
Description : What causes the maximum usable frequency to vary? A. The temperature of the ionosphere B. The speed of the winds in the upper atmosphere C. The type of weather just below the ionosphere D. The amount of radiation received from the sun
Last Answer : D. The amount of radiation received from the sun
Description : The greatest detrimental effect on idle electrical equipment, such as cargo pump motors, is the _____________. A. loss of residual magnetism B. absorption of moisture in the insulation C. insulation varnish flaking D. dirt collecting on the windings
Last Answer : Answer: B
Description : The rate of drug absorption is greatest in; A A. The small intestine B. The large intestine C. The stomach D. Plasma
Last Answer : The small intestine
Description : What is the main loss mechanism between the ultraviolet and infrared absorption regions?
Last Answer : Rayleigh scattering.
Description : Extrinsic (OH) absorption peaks define three regions or windows of preferred operation. List the three windows of operation.
Last Answer : The first, second, and third windows of operation are 850 nm, 1300 nm, and 1550 nm, respectively.
Description : Silica (pure glass) fibers are used because of their low intrinsic material absorption at the wavelengths of operation. This wavelength of operation is between two intrinsic absorption regions. What are these two regions called? What are the wavelengths of operation for these two regions?
Last Answer : Ultraviolet absorption region (below 400 nm) and infrared absorption region (above 2000 nm).
Description : What are the main causes of absorption in optical fiber?
Last Answer : Intrinsic and extrinsic material properties.
Description : When a wave is reflected from a surface, energy is transferred. When is the transfer of energy greatest?
Last Answer : When the incident wave is nearly parallel with the surface.
Description : What is the greatest danger to a transistor?
Last Answer : Heat.
Description : What is the greatest threat to a diode?
Description : If a transmitting antenna is placed close to the ground, how should the antenna be polarized to give the greatest signal strength?
Last Answer : Vertically polarized.
Description : What is the greatest limiting factor in a receiver’s detectable range
Last Answer : Noise.
Description : What factor has the greatest effect on the physical size of a coaxial cable?
Last Answer : The dielectric constant of the insulating material.
Description : Which gyro rotor in figure 3-6, view (A) view (B) view (C), will have the greatest rigidity if all are rotated at the same speed?
Last Answer : C.
Description : When a wave is reflected from a surface, energy is reflected. When is the reflection of energy the greatest?
Last Answer : When the wave is nearly parallel to the reflecting surface.
Description : At what instant does the greatest voltage appear across the resistor in a series RC circuit when the capacitor is charging?
Last Answer : At the instant of the initiation of the action.
Description : What type of core produces the greatest inductance?
Last Answer : Magnetic-metal core.
Description : Assertion `:-` Maximum absorption of food occur in jejunum. Reason `:-` Villi `&` microvilli abundantly present in small intestine.
Last Answer : Assertion `:-` Maximum absorption of food occur in jejunum. Reason `:-` Villi `&` microvilli abundantly ... . D. If both Assertion & Reason are false.
Description : Water absorption is mainly occur in `:-`
Last Answer : Water absorption is mainly occur in `:-` A. Colon B. Intestine C. Gastrium D. Appendix
Description : Where do most re-absorption of substances occur?
Last Answer : Need answer
Description : The following statement(s) is/are true concerning host defense mechanisms to intraabdominal infection. a. Bacterial clearance can occur via translymphatic absorption b. Phagocytic activity and bacterial killing can ... may be walled off but are seldom sealed by the omentum and other mobile viscera
Last Answer : Answer: a, b, c The introduction of microorganisms into the normally sterile peritoneal environment invoke several potent specialized host antimicrobial defense mechanisms. Bacterial clearance, ... the contaminated enteric contents walled off, preventing continued soilage of the peritoneal cavity
Description : The preferred route of administration of medication in the most acute care situations is which of the following routes? a) Intravenous The IV route is the preferred ... ) Intramuscular Intramuscular administration of medication is absorbed more slowly than intravenously administered medication.
Last Answer : a) Intravenous The IV route is the preferred parenteral route in most acute care situations because it is much more comfortable for the patient, and peak serum levels and pain relief occur more rapidly and reliably.
Description : Where do Sweat glands occur in greatest number? -Do You Know?
Last Answer : According to Henry Gray, the palm has around 370 sweat glands per square cm.,and back of hand has 200 persquare cm.
Description : What is the greatest number of points of intersection that can occur when 2 different circles and 2 different straight lines are drawn on the same piece of paper?
Last Answer : please answer
Description : Where do Sweat glands occur in greatest number?
Last Answer : the skin of the armpits
Description : The greatest induced EMF will occur in a straight wire moving at constant speed through a uniform magnetic field when the angle between the direction of the wire's motion and the direction of the magnetic field is w) 0 degrees x) 30 degrees y) 60 degrees z) 90 degrees
Last Answer : ANSWER: Z -- 90 DEGREES
Description : In what country do the greatest number of tornadoes occur?
Last Answer : ANSWER: UNITED STATES (Central and Southeastern portions)
Description : 1. Where do Sweat glands occur in greatest number? 2. What is the electorate for a Panchayat? 3. The cause of fractional atomic weights of elements? 4. The second largest river basin in India is ... 19. Why does Mumbai receives more rainfall than Pune? 20. What was the real name of Tantiya Tope?
Last Answer : Answer : 1 1. In the skin of the armpits 2. The Gram Sabha 3. The presence of Isotopes 4. Godavari 5. Guru Hargovind 6. Friedrich Engels 7. Cooperation 8. 30 9. Krishna Basin 10. ... Birds from reptiles 18. Dr. Rajendra Prasad 19. Because mumbai is on the windward side 20. Ramchandra Panduranga
Description : What condition must occur to have a change in the output of a D FF?
Last Answer : A positive-going clock pulse.
Description : In what layer of the atmosphere does virtually all weather phenomena occur?
Last Answer : Troposphere.
Description : At what point on an open-circuited rf line do voltage peaks occur?
Last Answer : At 1/2 wavelength from the end and at every 1/2 wavelength along the line
Description : List the three basic errors that occur during fiber alignment.
Last Answer : Fiber separation (longitudinal misalignment), lateral misalignment, and angular misalignment.