Description : Calculate the intensity of illumination at a distance of 0.5m from a source of light of power 200 candela assuming normal incidence.
Last Answer : Calculate the intensity of illumination at a distance of 0.5m from a source of light of power 200 candela assuming normal incidence.
Description : Lux is the SI unit of - (1) intensity of illumination (2) luminous efficiency (3) luminous flux (4) luminous intensity
Last Answer : (1) intensity of illumination Explanation: The SI unit of intensity of illumination (illuminance) is the lux. An illuminance of 1.0 lux is produced by 1.0 lumen of light shining on an area of 1.0 m2.
Description : Calculate the illuminance at a surface distance 0.5m from a ligth source of luminous intensity 200 cd, assuming normal incidence. If the area of the s
Last Answer : Calculate the illuminance at a surface distance 0.5m from a ligth source of luminous intensity 200 cd, ... , what is the luminous flux on this area ?
Description : A frosted bulb which may be taken as an isotropic source, gives as illumination of `8lm//m^(2)` at a distance of 5m. Calculate (i) its luminous intens
Last Answer : A frosted bulb which may be taken as an isotropic source, gives as illumination of `8lm//m^(2)` ... and (ii) the total luminous flux from the blub.
Description : Define each of following terms of illumination — lux, lumen, luminous flux, illumination.
Last Answer : i) Lux :- It is unit of illumination and it is defined as luminous flux falling per unit area ii) Lumen: It is defined as the luminous flux emitted by a source of one candle power per unit ... the given surface on the working plane. The unit of illumination is lumens/m2 OR lumens/m2 = 1 Lux
Description : An electric bulb illuminates a plane surface. The intensity of illumination on the surface at a point 2m away from the bulb is `5 xx 10^(-4)` phot. Th
Last Answer : An electric bulb illuminates a plane surface. The intensity of illumination on the surface at a point 2m away from the ... ? (1 phot `= 1m//cm^(2))`.
Description : Lux meter is used to measure…… a) Illumination level b) Sound intensity and illumination level c) Harmonics d) Speed
Last Answer : Illumination level
Description : Lux meter is used to measure…… c) Illumination level c) Harmonics d) Sound intensity and illumination level d) Speed
Description : Lux meter is used to measure…… a) Illumination level c) Harmonics b) Sound intensity and illumination level d) Speed
Description : A freshely prepared radioactive source of half 2 hours emits radiations of intensity which is 64 times the permissible safe level. The minimum time af
Last Answer : A freshely prepared radioactive source of half 2 hours emits radiations of intensity which is 64 times the ... 12 hours C. 24 hours D. 48 hours
Description : What is affected by the distance between the listener and the source of the sound because the intensity varies inversely with the square of the distance? A. Volume B. Pitch C. Loudness D. Frequency
Last Answer : C. Loudness
Description : Light intensity is generally described in terms of __________ and measured in _________. ∙ A. Luminous flux density; Lumens per unit area ∙ B. Luminous flux intensity; Lumens per unit area ∙ C. Luminous flux density; Lumens per unit volume ∙ D. Luminous flux intensity; Lumens per unit volume
Last Answer : Luminous flux density; Lumens per unit area
Description : Stars twinkle but planets do not twinkle because - (1) they emit light of a constant intensity (2) their distance from the earth does not change with time (3) they are very far away ... and hence we receive a greater amount of light and therefore minor variations in intensity are not noticeable
Last Answer : (4) they are nearer to the earth and hence we receive a greater amount of light and therefore minor variations in intensity are not noticeable Explanation: Eris is the most massive and second-largest ... orbiting the Sun, and the largest known body in the Solar System not visited by a spacecraft.
Description : Stars twinkle but planets do not twinkle because (1) they emit light of a constant intensity (2) their distance from the earth does not change with time (3) they are very far away from ... and hence we receive a greater amount of light and therefore minor variations in intensity are not noticeable
Last Answer : they are nearer to the earth and hence we receive a greater amount of light and therefore minor variations in intensity are not noticeable
Description : Does this Seiko men's diving watch have a source of illumination?
Last Answer : Seiko men's diving watch doesn't have any source of illumination
Description : At a distance of 10 meters form a point source, the intensity level is measured to be 70 dB. At what distance form the source well the intensity be 40 dB? How do you solve this?
Last Answer : Going on memory here….3db is half the intensity. The intensity is usually inversely proportional to r squared. The rest is math, so 70–40 is 30 or ten halves.
Description : Calculate workers left and discharged from the following: Labour turnover rates are 20%, 10% and 6% respectively under Flux method, Replacement method and Separation method. No. of workers replaced during the quarter is 80. (a) 112 (b) 80 (c) 48 (d) 64
Last Answer : (c) 48
Description : An overload in which of the listed motors will result in the illumination of an indicating light at the propulsion control station alarm panel? A. Fuel pump motor B. Steering motor C. Condensate pump motor D. Forced draft blower motor
Last Answer : Answer: B
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
Description : In interference experiment, monochromatic light is replaced by white light, we will see (a) Uniform illumination of screen (b) Uniform darkness on the screen (c) Equally spaced dark and white bands (d) Few colored bands and then general illumination
Last Answer : (d) Few colored bands and then general illumination
Description : A far-sighted person, without optical correction, is typically able to see nearby objects more clearly in bright light. The reason for this phenomena is: w) bright light provides better ... bright light causes squinting which flattens the eyeball which tends to correct the far-sighted condition.
Last Answer : ANSWER: X -- THE PUPIL OF THE EYE NARROWS WHICH INCREASES THE DEPTH OF FOCUS
Description : A 60W lamp is rated at 0.8 watt/candela. Calculate (i) luminous intensity of the lamp, (ii) luminous flux of the lamp, and (iii) illuminance at a dist
Last Answer : A 60W lamp is rated at 0.8 watt/candela. Calculate (i) luminous intensity of the lamp, (ii) ... iii) illuminance at a distance of 2m from the lamp.
Description : In convection heat transfer, if heat flux intensity is doubled then temperature difference between solid surface and fluid will ?
Last Answer : Get doubled.
Description : The electric field intensity of a field with velocity 10m/s and flux density of 2.8 units is a) 0.28 b) 28 c) 280 d) 10/2.8
Last Answer : b) 28
Description : Which quantity is solenoidal in the electromagnetic theory? a) Electric field intensity b) Electric flux density c) Magnetic field intensit d) Magnetic flux density
Last Answer : d) Magnetic flux density
Description : The line integral of the magnetic field intensity is the a) Current density b) Current c) Magnetic flux density d) Magnetic moment
Last Answer : b) Current
Description : Find the magnetic field intensity of a material with flux density of 24 units in air(in 10 6 order) a) 19.09 b) 21 c) 25 d) 26.78
Last Answer : a) 19.09
Description : Calculate the energy when the magnetic intensity and magnetic flux density are 15 and 65 respectively. a) 755 b) 487.5 c) 922 d) 645
Last Answer : b) 487.5
Description : The magnetic flux density is directly proportional to the magnetic field intensity. State True/False. a) True b) False
Last Answer : a) True
Description : If the electric potential is given, which of the following cannot be calculated? a) Electrostatic energy b) Electric field intensity c) Electric flux density d) Permittivity
Last Answer : a) Electrostatic energy
Description : Calculate the energy in an electric field with flux density 6 units and field intensity of 4 units. a) 12 b) 24 c) 36 d) 48
Last Answer : a) 12
Description : Find the electric flux density surrounding a material with field intensity of 2xyz placed in transformer oil ( εr = 2.2) at the point P(1,2,3) is (in 10 -10 units) a) 2.1 b) 2.33 c) 2.5 d) 2.77
Last Answer : c) 2.5
Description : The electric flux density and electric field intensity have which of the following relation? a) Linear b) Nonlinear c) Inversely linear d) Inversely nonlinear
Last Answer : a) Linear
Description : Gauss law cannot be used to find which of the following quantity? a) Electric field intensity b) Electric flux density c) Charge d) Permittivity
Last Answer : d) Permittivity
Description : The electric flux density is the a) Product of permittivity and electric field intensity b) Product of number of flux lines and permittivity c) Product of permeability and electric field intensity d) Product of number of flux lines and permeability
Last Answer : a) Product of permittivity and electric field intensity
Description : The ultimate result of the divergence theorem evaluates which one of the following? a) Field intensity b) Field density c) Potential d) Charge and flux
Last Answer : d) Charge and flux
Description : Which one of the following quantities forms the basis of radiometry? (A) Radiant energy (Q) (B) Radiant flux ( ) (C) Radiant intensity (I) (D) All of these
Last Answer : Answer: Option D
Description : It is an energy flux, equal to the rate of energy flow per unit area per unit time across some surface. a. Irradiance b. Radiant Intensity c. Luminosity d. Brightness
Last Answer : Luminosity
Description : The ratio of intensity of magnetisation to the magnetisation force is known as (a) flux density (b) susceptibility (c) relative permeability (d) none of the above
Last Answer : (b) susceptibility
Description : Which of the following is a vector quantity ? (a) Relative permeability (b) Magnetic field intensity (c) Flux density (d) Magnetic potential
Last Answer : (b) Magnetic field intensity
Description : The space around the charge within which other charges are influenced by it is called: (a) Electric field (b) Magnetic field (c) Electric flux (d) Electric intensity
Last Answer : a) Electric field
Description : The number of electric field lines passing through a certain element of area is called: (a) Electric lines of force (b) Electric intensity (c) Electric flux (d) None of these
Last Answer : (c) Electric flux
Description : Define the following terms and state their units: (i) Luminous intensity, (ii) Luminous flux
Last Answer : i) Luminous intensity: This is defined as the luminous flux emitted into a solid angle of space in a specific direction. Its unit is the candela. OR The luminous flux per unit solid angle ( ... energy radiated by the light source in all direction. The unit of luminous flux is lumen (lm)
Last Answer : The electric flux and field intensity inside a conducting sphere is: zero.
Description : The potentiometers shown in the illustration are supplied with both (+) and (-) voltages as well as a reference to ground ________________. EL-0095 A. so there is always a spare power ... , the other for relay operation and the potentiometers are in positions where they can be accidentally touched
Last Answer : Answer: C
Description : Pick out the wrong statement. (A) Strongly caking coal should not be used in the Lurgi gasifier (B) Acetylene gas cannot be used for illumination purpose (C) Water gas is called blue gas ... is burnt (D) Gaseous fuels require less percentage of excess air for combustion as compared to liquid fuels
Last Answer : (B) Acetylene gas cannot be used for illumination purpose
Description : A light year is a unit of – (1) time (2) distance (3) speed of light (4) intensity of light
Last Answer : (2) distance Explanation: As defined by the International. Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year. It is a measure of distance (rather than, as is sometimes misunderstood, a measure of time).
Description : Light year is a unit of - (1) time (2) distance (3) light (4) intensity of light
Last Answer : (2) distance Explanation: A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second.
Description : Which instrument is used to measure the intensity of light produced by an unknown source in terms of a standard source?
Last Answer : Photometre
Description : The energy associated with one photon of a light beam is proportional to one of the following. Is it proportional to: w) the intensity of the light source from which it came x) the number of photons in the beam y) the frequency of the photon z) the speed of the photon
Last Answer : ANSWER: Y -- THE FREQUENCY OF THE PHOTON