A light source emits monochromatic light of wavelength 555 nm. The source consumes 100 W of electric power and emits 35 W of radiant flux. Calculate the overall luminous efficiency.
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An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
(d) 5 A rating must be used
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A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
Power is given by the expression, Power=Work done /Time Work done = Energy consumed by the lamp = 1000 J Power=1000 / 10 = 100 Js−1 = 100 W
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When a monochromatic light having only one wavelength, passes through a prism, will it show dispersion?
No, it will not show dispersion. It will only show deviation.
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A LASER is a source of very intense, monochromatic, and unidirectional beam of light. These properties of a laser light can be exploited
Time taken by the laser beam to return to Earth after reflection from the Moon = 2.56 s Speed of light = 3 × 108 m/s Time taken by the laser beam to...
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Define 1 Watt of power. A lamp consumes 1000 J of electrical energy in 10s. Calculate its power
A body is said to have power of 1 watt if it does work at the rate of 1 joule in 1 s, i.e., 1W=1J/1s Power is given by the expression, Power=Work done...
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A source emits light of wavelengths 555 nm and 600nm. The radiant flux of the 555 nm part is 40 W
The radiant flux of 555nm part is 40W and of the 600nm part is 30W (a) Total radiant flux = 40W + 30W = 70W (b) Luminous flux = (L.Fllux)555nm + (L.Flux)600nm =...
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Mark the correct options. (a) The luminous efficiency of a monochromatic source is always greater than that of a white light source of same power.
(b) The luminous efficiency of a monochromatic source of wavelength 555 nm is always greater than that of a white light source of same power. (c) The illuminating power of a...
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A 25 watt bulb emits monochromatic light of wave length 0.75 x10^-6 meter . calculate rate of emission of quanta per sec
W= pxt W=25 x 1 J n = w/hc/ ʎ =25x 0.75 x10-6 /6.626x 10-34x 3x 108 =7.18 x 1019
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A gas of hydrogen-like ions is prepared in a particular excited state A. It emits photons having wavelength equal to the wavelength
a) The gas emits 6 wavelengths, let it be in nth excited state. => n(n-1)/2=6=>n=4 So, The gas is in 4th excited state. b) Total no.of wavelengths in the transition is 6. We have ...
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An atom absorbs a photon of wavelength 500 nm and emits another photon of wavelength 700 nm.
λ1 = 500 nm = 500 x 10–9m, λ2 = 700 nm = 700 x 10–9 m E1 – E2 = Energy absorbed by the atom in the process. = hc [1/λ1 – 1/λ2] =>...
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