What is the typical wavelength of light emitted from epitaxially grown LEDs? ∙ a. 840 nm  
∙ b. 490 nm  
∙ c. 480 nm  
∙ d. 940 nm

1 Answer

Answer :

∙ d. 940 nm

Related questions

Description : The first laser emitted ∙ a. Pulses of 694 nm red light ∙ b. A continuous red beam ∙ c. Pulses of white light from a helical flash lamp ∙ d. Spontaneous emission

Last Answer : ∙ a. Pulses of 694 nm red light

Description : Infrared light has a wavelength that is ∙ A. less than 400 nm ∙ B. more than 700 nm ∙ C. less than 700 nm ∙ D. a little over 400 nm

Last Answer : B. more than 700 nm

Description : ange of wavelength of visible light ∙ A. 670 nm to 10^3 nm ∙ B. 440 nm to 540 nm ∙ C. 110 nm to 240 nm ∙ D. 390 nm to 770 nm

Last Answer : D. 390 nm to 770 nm

Description : The wavelength of visible light extends from ∙ a. 0.8 to 1.0 nm ∙ b. 400 to 750 nm ∙ c. 200 to 660 nm ∙ d. 700 to 1200 nm

Last Answer : b. 400 to 750 nm

Description : The laser frequency when the light has the wavelength 800 nm is ∙ a. 375 x 1012 Hz ∙ b. 475 x 1015 Hz ∙ c. 375 x 109 Hz ∙ d. 375 x 1018 Hz

Last Answer : d. 375 x 1018 Hz

Description : Light rays that are emitted simultaneously from an LED and propagated down an optical fiber do not arrive at the far end of the fiber at the same time results to ∙ A. intramodal dispersion ∙ B. pulse length dispersion ∙ C. modal dispersion ∙ D. wavelength dispersion

Last Answer : D. wavelength dispersion

Description : The wavelength of a visible extends from ∙ A. 0.8 to 1.6 um ∙ B. 400 to 750 nm ∙ C. 200 to 660 nm ∙ D. 700 to 1200 nm

Last Answer : B. 400 to 750 nm

Description : How many modes possible with a multimode step-index with a core diameter of 50 um, a core refractive index of 1.6, a cladding refractive index of 1.584, and a wavelength of 1300 nm. ∙ A. 456 ∙ B. 213 ∙ C. 145 ∙ D. 372

Last Answer : D. 372

Description : Why are visible-light LEDs not used for fiber optics? ∙ a. It has high losses ∙ b. It has short wave ∙ c. It has low attenuation ∙ d. It has weak signal

Last Answer : ∙ a. It has high losses

Description : Both LEDs and ILDs operate correctly with ∙ A. forward bias ∙ B. reverse bias ∙ C. neither forward nor reverse bias ∙ D. either forward or reverse bias

Last Answer : A. forward bias

Description : Both LEDs and ILDs operate correctly with ∙ a. Forward bias ∙ b. Reverse bias ∙ c. Neither A or B ∙ d. Either A or B

Last Answer : a. Forward bias

Description : What is the lifetime of LEDs? ∙ a. 200,000 minutes ∙ b. 200,000 hours ∙ c. 150,000 minutes ∙ d. 150,000 hours

Last Answer : a. 200,000 minutes

Description : Which laser emits light in the visible range 400 to 700 nm? ∙ a. Argon-ion ∙ b. Nitrogen ∙ c. Carbon-dioxide ∙ d. Neodymium-YAG

Last Answer : a. Argon-ion

Description : The law that states “When visible light of high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted” is known as ____________. ∙ A. Einstein law of photon ∙ B. Marconi’s law ∙ C. Maxwell’s law ∙ D. Plank’s law

Last Answer : D. Plank’s law

Description : Is the width of the range of wavelengths emitted by the light source ∙ a. Bandwidth ∙ b. Chromatic Dispersion ∙ c. Spectral width ∙ d. Beamwidth

Last Answer : c. Spectral width

Description : What is the spectral width of an ILD? ∙ A. 0.1 nm to 1 nm ∙ B. 2 nm to 5 nm ∙ C. 1 nm to 3 nm ∙ D. 3 nm to 4 nm

Last Answer : C. 1 nm to 3 nm

Description : What is the spectral width of a standard LED? ∙ A. 20 to 40 nm ∙ B. 30 to 50 nm ∙ C. 10 to 30 nm ∙ D. 40 to 60 nm

Last Answer : 30 to 50 nm

Description : Range of wavelengths of ultraviolet ∙ A. 670 nm to 10^3 nm ∙ B. 440 nm to 540 nm ∙ C. 110 nm to 240 nm ∙ D. 10 nm to 390 nm

Last Answer : D. 10 nm to 390 nm

Description : Range of infrared ∙ A. 360 nm to 440 nm ∙ B. 670 nm to 10^3 nm ∙ C. 110 nm to 240 nm ∙ D. 770 nm to 10^6 nm

Last Answer : D. 770 nm to 10^6 nm

Description : The graded-index multimode optical fiber has a core diameter of _____ nm. ∙ a. 0.5 ∙ b. 0.05 ∙ c. 0.0005 ∙ d. 5

Last Answer : ∙ a. 0.5

Description : A step-index multimode optical fiber has a core diameter of _____ nm. ∙ a. 0.02 ∙ b. 0.2 ∙ c. 2 ∙ d. 0.002

Last Answer : b. 0.2

Description : A single mode optical fiber has a core diameter of _____ nm. ∙ a. 0.1 ∙ b. 0.01 ∙ c. 0.2 ∙ d. 0.05

Last Answer : a. 0.1

Description : Infrared range for fiber optics ∙ a. 400 – 700 nm ∙ b. 700 – 1200 nm ∙ c. 300 – 2000 nm ∙ d. 400 – 7000 nm

Last Answer : b. 700 – 1200 nm

Description : A popular light wavelength fiber-optic cable is ∙ A. 0.7 micrometer ∙ B. 1.3 micrometer ∙ C. 1.5 micrometer ∙ D. 1.8 micrometer

Last Answer : B. 1.3 micrometer

Description : The higher the index number ∙ A. the higher the speed of light ∙ B. the lower the speed of light ∙ C. has no effect on the speed of light ∙ D. the shorter the wavelength propagation

Last Answer : B. the lower the speed of light

Description : Which of the following terms best describes the reason that light is refracted at different angles? ∙ A. Photon energy changes with wavelength ∙ B. Light is refracted as a function of surface smoothness ∙ ... determined partly by a and b ∙ D. The angle is determined by the index of the materials

Last Answer : ∙ D. The angle is determined by the index of the materials

Description : What is the unit of light wavelength? ∙ a. Micrometer ∙ b. Angstroms ∙ c. Mils ∙ d. Fathom

Last Answer : ∙ b. Angstroms

Description : What parameter of light detector determines the range or system length that can be achieved for a given wavelength? ∙ a. Transit time ∙ b. Spectral response ∙ c. Dark current ∙ d. Responsitivity

Last Answer : ∙ b. Spectral response

Description : ______ dispersion is caused by the difference in the propagation times of light rays that take different paths down a fiber. ∙ a. Material dispersion ∙ b. Wavelength dispersion ∙ c. Modal dispersion

Last Answer : ∙ c. Modal dispersion

Description : The wavelength of light has no role in ∙ a. Diffraction ∙ b. Interference ∙ c. Polarization ∙ d. Reflection

Last Answer : c. Polarization

Description : When a beam of light enters one medium from another, which quantity will not change? ∙ a. Direction ∙ b. Speed ∙ c. Frequency ∙ d. Wavelength

Last Answer : c. Frequency

Description : Is the different angle of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitted. ∙ a. Acceptance angle ∙ b. Modes ∙ c. Sensors ∙ d. Aperture

Last Answer : b. Modes

Description : Which color has the shortest wavelength of light? ∙ a. Red ∙ b. Yellow ∙ c. Blue ∙ d. Green

Last Answer : c. Blue

Description : The _____ is equal to the number of electrons emitted per second times the electron charge ∙ a. Intensity ∙ b. Optical power ∙ c. Photocurrent ∙ d. Responsitivity

Last Answer : c. Photocurrent

Description : Which is the proper measurement of average power emitted by a pulsed laser? ∙ a. Energy x time ∙ b. Pulse energy x repetition rate ∙ c. Pulse energy / repetition rate ∙ d. Peak power x pulse length

Last Answer : ∙ b. Pulse energy x repetition rate

Description : The range of wavelength values that a given photodiode will respond. ∙ A. spectral response ∙ B. permeance ∙ C. dark current ∙ D. reluctance

Last Answer : A. spectral response

Description : The bandwidth of a fiber is limited by ∙ a. Mode ∙ b. Wavelength ∙ c. Dispersion ∙ d. Frequency

Last Answer : c. Dispersion

Description : Modal dispersion is caused by the ∙ a. Dependence of wavelength on index of refraction ∙ b. Dependence of propagation constant on index of refraction ∙ c. Dependence of the propagation constant on the wavelength ∙ d. Dependence of the propagation constant on the mode number

Last Answer : d. Dependence of the propagation constant on the mode number

Description : Material dispersion is caused by the ∙ a. Wavelength dependence of the index of refraction ∙ b. Wavelength independence of the index of refraction ∙ c. Dependence of the propagation constant on the mode number ∙ d. Independence of the propagation constant on the mode number

Last Answer : d. Independence of the propagation constant on the mode number

Description : If six men working 8 hours a day earn Rs.840 per week, then 9 men working 6 hours per day will earn per week a) Rs. 940 b) Rs. 945 c) Rs. 1620 d) Rs. 1680 e) Rs. 1245

Last Answer : b) Rs. 945

Description : X invested three- nineth, Y invested three-seventh of the remaining and Zth remaining. If Y earned Rs.840 as profit pr each year. Find the average monthly profit of all. A) 510 B) 490 C) 630 D) 370 

Last Answer : Answer: B) Let total amount puts by X, Y& Z be P X's investment = 3/9 P Balance investment =6/9 p Y's investment =6/9*P*3/7=2/7 P Remaining investment =8 p/21 =Z's amounts Profit ratio ... :6:8 1month share =840/12=Rs .70 Average monthly profit of X, Y, Z=70/3 *21 =Rs.490

Description : LASER stands for: a. Light Amplification by Simulated Emission of Radiation b. Light Amplification by Stimulated Emission of Radiation c. Light Amplification by Simulated Emitted Rays d. Light Amplification by Stimulated Emitted Rays

Last Answer : b. Light Amplification by Stimulated Emission of Radiation

Description : Refraction is the ∙ A. bending of light ∙ B. reflection of light waves ∙ C. distortion of light waves ∙ D. diffusion of light waves

Last Answer : A. bending of light

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 : EMD is best described by which statement? ∙ A. 70 percent of the core diameter and 70% of the fiber NA should be filled with light. ∙ B. 70 percent of the fiber diameter and 70% of the ... be measured at the output. ∙ D. 70 percent of the unwanted wavelengths should be attenuated by the fiber.

Last Answer : 70 percent of the core diameter and 70% of the fiber NA should be filled with light.

Description : The speed of light in plastic compared to the speed of light in air is ∙ A. less ∙ B. more ∙ C. the same ∙ D. zero

Last Answer : A. less

Description : The upper pulse rate and information-carrying capacity of a cable is limited by ∙ A. pulse shortening ∙ B. attenuation ∙ C. light leakage ∙ D. modal dispersion

Last Answer : D. modal dispersion

Description : Total internal reflection takes place if the light ray strikes the interface at an angle with what relationship to the critical angle? ∙ A. less than ∙ B. greater than ∙ C. equal to ∙ D. zero

Last Answer : ∙ B. greater than

Description : The minimum optical power a light detector can receive and still produce a usable electrical output signal. ∙ A. light responsivity ∙ B. light sensitivity ∙ C. light collectivity ∙ D. illumination

Last Answer : B. light sensitivity