Description : What is one of the major reasons for the fading of radio waves which have been reflected from a surface?
Last Answer : Shifting in the phase relationships of the wave.
Description : In Fraunhofer diffraction pattern for single slit, a central maximum is obtained when angle of diffraction q is equal to zero. What it actually indicates? A. All the diffracted rays are parallel and focused ... are diffracted by the slit in all the directions D. The rays are reflected by the slit
Last Answer : A. All the diffracted rays are parallel and focused by slit at a single point on screen
Description : Standing waves are formed when two sets of waves of equal amplitude and frequency w) are in phase x) are in opposite phase y) move through each other in opposite directions z) are reflected from the same surface
Last Answer : ANSWER: Y -- MOVE THROUGH EACH OTHER IN OPPOSITE DIRECTIONS
Description : Microwaves are electromagnetic waves with frequency, in the range of which unit? -Do You Know?
Last Answer : Microwaves have frequencies ranging from about 1 billion cycles per second, or 1 gigahertz (GHz), up to about 300 gigahertz and wavelengths of about 30 centimeters (12 inches) to 1 millimeter (0.04 inches),
Description : Which of the following is used in oven? (1) X-rays (2) UV-rays (3) Microwaves (4) Radio waves
Last Answer : (3) Microwaves Explanation: An oven is a thermally insulated chamber used for the heating, baking or drying of a substance and most commonly used for cooking.
Description : Waves that are required for long distance wireless communication are – (1) Infrared rays (2) Ultraviolet rays (3) Radio waves (4) Microwaves
Last Answer : (3) Radio waves Explanation: Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor. With radio waves distances can be short ... , or as far as thousands or even millions of kilometres for deep-space radio communications.
Description : To measure the speed of an approaching car a police officer shines – (1) light waves on it (2) microwaves on it (3) radio waves on it (4) ultra high frequency waves on it
Last Answer : (3) radio waves on it Explanation: Radar, which stands for radio detection and ranging, is a system that uses reflected radio waves to detect objects and measure their distance and speed. For example, police use radar to calculate the speed of cars.
Description : Radio waves, microwaves, infra-red spectrum, ultraviolet rays, X-rays and gamma rays are classified as ______. (1) light waves (2) electromagnetic waves (3) electric waves (4) magnetic waves
Last Answer : (2) electromagnetic waves Explanation: Electromagnetic radiation is the radiant energy released by certain electromagnetic processes. It consists of electromagnetic waves which are synchronized oscillations of electric and magnetic fields that propagate at the speed of light through a vacuum.
Description : ________ are usedfor short-range communications such as those between a PC and aperipheral device. A) Radio waves B) Microwaves C) Infrared waves D) none of the above
Last Answer : Infrared waves
Description : _____ are used for cellular phone, satellite,and wireless LAN communications. A) Radio waves B) Microwaves C) Infrared waves D) none of the above
Last Answer : Microwaves
Description : …….are used for short-range communications such as those between a PC and aperipheral device. a. Radio waves b. None of These c. Microwaves d. Infrared waves
Last Answer : d. Infrared waves
Description : ……………are used for cellular phone, satellite, and wireless LAN communications. a. Microwaves b. Radio waves c. None of these d. Infrared waves
Last Answer : a. Microwaves
Description : They wrote a paper describing how it was possible to use stimulated emission for amplifying light waves (laser) as well as microwaves (maser). ∙ A. Theodore Maiman ∙ B. KC Kao and GA Bockham ∙ C. Charles Townes and Arthur Schawlow ∙ D. Kapron, Keck and Maurer
Last Answer : C. Charles Townes and Arthur Schawlow
Description : They wrote a paper describing how it was possible to use stimulated emission for amplifying light waves (laser) as well as microwaves (maser).
Last Answer : Charles Townes and Arthur Schawlow
Description : Which wave has the highest frequency? w) microwaves x) infrared waves y) ultraviolet waves z) radio waves
Last Answer : ANSWER: Y -- ULTRAVIOLET WAVES
Description : 1. How many orangutans disappear each year as result of palm oil farming? 2. Who decides about the reasonableness of the restrictions placed on Fundamental Rights? 3. Microwaves are electromagnetic waves with ... 19. Where is Over 90% of the world's biomass? 20. Who deciphered the Brahmi script?
Last Answer : Answer : 1. 5000 2. Courts 3. Giga hertz 4. Tundra region 5. Kharavela 6. MRF 7. Lillehammer 8. Javan rhino 9. Evergreen forests 10. Prakrit 11. Directive Principle 12. An atom 13. Rs. 100 ... 16. Arati Saha 17. A greater flamingo 18. Finance Bills 19. In tropical rain forests 20. James Princep
Description : Which of the following statements is not true with respect to microwaves? (A) Electromagnetic waves with frequencies from 300 GHz to 400 THz. (B) Propagation is line-of-sight. (C) Very ... waves cannot penetrate walls. (D) Use of certain portions of the band requires permission from authorities.
Last Answer : (A) Electromagnetic waves with frequencies from 300 GHz to 400 THz.
Description : Waves that are required for long distance wireless communication are (1) Infrared rays (2) Ultraviolet rays (3) Radio waves (4) Microwaves
Last Answer : Radio waves
Description : To measure the speed of an approaching car a police officer shines (1) light waves on it (2) microwaves on it (3) radio waves on it (4) ultra high frequency waves on it
Last Answer : radio waves on it
Description : Which semiconductor sources (LD or LED) emit more focused light and are capable of launching sufficient optical power into both single mode and multimode fibers?
Last Answer : LDs.
Description : A sound wave that is reflected back toward the source is known as what type of sound?
Last Answer : Echo.
Description : The layer of the atmosphere in which Radio Waves are reflected back is called- (1) Ionosphere (2) Troposphere (3) Stratosphere (4) Exosphere
Last Answer : (1) Ionosphere Explanation: The Radio waves are reflected back to Earth in the Ionosphere which is an electrically charged layer of the upper atmosphere. This process is used to communicate beyond the horizon, atintercontinental distances, mostly in the shortwave frequency bands.
Description : Speed of sound in water is 1500 m s-1, depth of water when reflected sound waves are detected after 0.40 s is A. 700 m B. 600 km C. 600 m D. 750 km
Last Answer : 600 m
Description : Heat waves (A) Cannot pass through vacuum (B) Travel in straight line (C) Can be reflected by a mirror (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Pick out the wrong statement (A) The concentric atmosphere layer just above troposphere is called stratosphere, which is rich in ozone (B) Mesosphere is characterised by very low atmospheric ... radio waves used in the long distance radio communication are reflected back to earth by stratosphere
Last Answer : (D) The radio waves used in the long distance radio communication are reflected back to earth by stratosphere
Description : Remote sensing techniques make use of the properties of ___________ emitted, reflected or diffracted by the sensed objects: (A) Electric waves (B) Sound waves (C) Electromagnetic waves (D) Wind waves
Last Answer : Answer: Option C
Description : Radio waves are reflected back from which layer of the Earth's atmosphere?
Last Answer : Ionosphere
Description : At what frequency compared to the cutoff frequency of a waveguide will the wavefronts be reflected back and forth across the guide (setting up standing waves) and no energy
Last Answer : UHF receiving antenna
Description : When electromagnetic waves strike the boundary of denser medium they are __________. A. Reflected, in phase B. Reflected out of phase by 180° C. reflected, they are completely absorbed
Last Answer : B. Reflected out of phase by 180°
Description : Bats detect the obstacles in their path by receiving the reflected ______. a) infrasonic waves c) ultrasonic waves b) electromagnetic waves d)radio waves
Last Answer : c) ultrasonic waves
Description : The layer of the atmosphere in which Radio Waves are reflected back is called ; (1) Ionosphere (2) Troposphere (3) Stratosphere(4) Exosphere
Description : What happens to reflected energy that enters a directional coupler that is designed to sample incident energy?
Last Answer : . The reflected energy adds at the absorbent material and is absorbed.
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 factor determines whether a radio wave is reflected or refracted by the ionosphere?
Last Answer : Thickness of ionized layer.
Description : In fiber-to-fiber connections, Fresnel reflection is one source of coupling losses. Light is reflected back into the source fiber and is lost. What causes Fresnel reflection?
Last Answer : A step change in refractive index that occurs at fiber joints, caused by fiber separation.
Description : A wavefront undergoes a phase change as it travels along the fiber. If the wavefront transverses the fiber twice and is reflected twice and the total phase change is equal to 1/2 p, will the wavefront disappear? If yes, why?
Last Answer : Yes, the wavefront will disappear because the total amount of phase collected must be an integer multiple of 2 p. (If the propagating wavefronts are out of phase, they will disappear. ... interfere with the wavefronts out of phase. This type of interference is called destructive interference.)
Description : What condition causes a light ray to be totally reflected back into its medium of propagation?
Last Answer : Total internal reflection occurs when the angle of refraction approaches 90 degrees. This condition occurs when the angle of incidence increases to the point where no refraction is possible.
Description : When light strikes a piece of white paper, the light is reflected in all directions. What do we call this scattering of light?
Last Answer : Diffusion.
Description : A light wave enters a sheet of glass at a perfect right angle to the surface. Is the majority of the wave reflected, refracted, transmitted, or absorbed?
Last Answer : Transmitted.
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 : What type circuit is used to produce square or rectangular waves?
Last Answer : Multivibrator.
Description : A substance that is unable to transmit any light waves is known as what type of substance?
Last Answer : Opaque.
Description : A substance that transmits almost all of the light waves falling upon it is known as what type of substance?
Last Answer : Transparent.
Description : Which one of the following statements is not correc t? (a) Parallax error is eliminated when there is no change in the staff reading when eye is moved up and down (b) The objective lens is ... (d) The eyepiece need not be adjusted after the first set up when the same surveyor is taking readings
Last Answer : (b) The objective lens is to be focused towards a white or bright background for clear visibility of cross-hairs
Description : Where is the microwaves radiation located on the electromagnetic spectrum in relation to other kinds of radiation?
Last Answer : Microwaves are in the UHF portion of the spectrum. Typicalfrequencies are above 100 GHz.
Description : The main benefit of light-wave communications over microwaves or any other communications media is a. Lower cost b. Better security c. Wider bandwidth d. Freedom from interference
Last Answer : c. Wider bandwidth
Description : The main benefit of light wave communications over microwaves or any other communications media are ∙ A. lower cost ∙ B. better security ∙ C. wider bandwidth ∙ D. freedom from interface
Last Answer : C. wider bandwidth
Description : The main benefit of light-wave communications over microwaves or any other communications media is ∙ a. Lower cost ∙ b. Better security ∙ c. Wider bandwidth ∙ d. Freedom from interference
Description : Compared to the velocity of propagation of waves in air, what is the velocity of propagation of waves in waveguides?
Last Answer : Slower.
Description : What is the term for multiple reflections of sound waves?
Last Answer : Reverberation.