The different colours of different stars are due to the variation of – (1) temperature (2) pressure (3) density (4) radiation from them

The different colours of different stars are due to the variation of – (1) temperature (2) pressure (3) density (4) radiation from them
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(1) temperature Explanation: Shortly after blackbody radiation was understood, it was noticed that the spectra of stars look extremely similar to blackbody radiation curves of various temperatures, ranging from a few thousand Kelvin to ~50,000 Kelvin. The obvious conclusion is that stars are similar to blackbodies, and that the colour variation of stars is a direct consequence of their surface temperatures.
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The different colours of different stars are due to the variation of (1) temperature (2) pressure (3) density (4) radiation from them

Description : The different colours of different stars are due to the variation of (1) temperature (2) pressure (3) density (4) radiation from them

Last Answer : temperature

Pick up the correct statement from the following: (A) The refractive index of a medium varies according to the wavelength of the radiation, (B) The variation of the refractive index with wave length, is called dispersion, (C) The splitting of colours of white light by passing through a prism is caused due to dispersion (D) All of these

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Description : The colours of stars depend on their – (1) temperature (2) distance (3) radius (4) atmospheric pressure

Last Answer : (1) temperature Explanation: The colour of a star tells about its temperature, and the temperature depends on some combination of the star's mass and evolutionary phase.

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Description : The colours of stars depend on their (1) temperature (2) distance (3) radius (4) atmospheric pressure

Last Answer : temperature

How does the flow of air occur in natural draught cooling towers? a) Natural pressure head density between cold outside air and humid inside air b) Variation in pressure of both cold outside air and humid inside air c) Due to the given air vents and vacuum ports d) Because of difference in the volume of both the of airs

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The variation of atmospheric potential is caused due to: (A) Difference in temperature over the surface of the earth (B) Change in the density of air (C) Both (a) and (b) (D) Neither (a) nor (b)

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A small gap is left at the joints of rails in a railway track to – (1) avoid the tracks being distorted due to seasonal temperature variation (2) avoid the heating of tracks to high temperature (3) control the speed of train (4) keep the rails equidistant

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Last Answer : avoid the tracks being distorted due to seasonal temperature variation

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Utilizing the answer to the previous problem, estimate the overall or average increase in temperature ( ΔT) of the concrete roof from the energy absorbed from the sun during a12hour day. Assume that all of the radiation absorbed goes into heating the roof. The specific heat of concrete is about 900 J/kg, and the density is about 2,300 kg/m3 .  a. 7.9 °C  b. 8.9°C  c. 9.9°C  d. 10.9°C formula: ΔQ = m c ΔT

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Last Answer : 7.9 °C