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Scattering, Blue Sky, reddish sun

Sun appears blue in midday because blue light with shorter wavelength scattered most. Agreed.

Sun appears red in sunrise and sunset because sunlight travels larger distance in atmosphere.
Then why cannot blue light scatter more during sunrise and sunset??

I can’t relate the reason for blue and red of sun as the concept behind them is different.
Please Explain??

Asked Rahul Verma


Please see that during daytime SKY appears blue (not sun) because when we look at sky, it is the scattered light reaching our eyes and blue light (the blue region of the spectrum) is scattered the most and at sunrise and sunset the SUN  appears reddish because the blue light is scattered and lost. The light coming directly from sun contains less amount of blue and the sun appears reddish.

Problem from electricity

A 100 m long thread carries charges uniformly distributed along its length. An

electron, 10 cm away from the centre of the thread along a line perpendicular to the
thread experiences an attractive force of 2.7 × 10−12N. Calculate the total charge on
the thread.

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I have been considering space-time and would like somebody smart to let me know if this is really dumb or not. I don’t know anything about Physics,
so I may be breaking a dozen rules with the thought, but I just have to put this out there.
1. Is there a ‘Frame Rate’ of the universe? (How many frames per second?)
2. Is the time between frames constant (ie. 1 light second between 1 frame to it’s next frame.)
3. (Simplified numbers here, I am a simpleton) Assuming a Constant time rate of 1 light minute between time frames…
If, in flat, space-time moveing truly zero miles per hour, there are 1 frames per minute, then it takes
10 frames to progress 10 minutes through time and the constant will always be 1 light minute. (Constant remains the
same under all circumstances)
When you move nearer to an immense object (A Black Hole), lets say 100 light miles away,
the number of frames doubles from 10 to 20 to span the same 10 minute time span, BUT the constant time between frames must stay the same.
So, from the original oberservers point of view, the participant is moveing more slowly through time (2 times longer to span the 10 minute.).
Move the scenerio half again closer to the Black Holes Singularity and the frames double again (20 frames to 40 frames).
So, again from the original observers point of view, the participant is moving even more slowly through time.
The time frame will continue to grow exponentially each time you move the participant closer to the singularity
This would mean that the participant would never be able to reach the singularity and, to the original observer, the participant would
seemingly become frozen in time.
This idea would allow for information falling into a black hole to not be destroyed, but rather simply beyond our ability to reach it.

The above idea works the same with speed. The faster you travel through space, the more frames between time spans you have. Thus
again, never allowing you to reach C (lightspeed).

Please let me know just how far away from reality my thought is.
Thank you for you time,
John Thatcher

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Hope that all have performed well in the CBSE Physics exam. If you found any problem with any of the questions or the pattern you may post your comments here.

Very Important Portions for class 12 Physics for CBSE Board Exam 2017

Please revise these portions thoroughly

  • Electric Dipole : electric field due to a dipole on axial line and equatorial line, torque on a dipole in a uniform electric field, work done in rotating a dipole, potential energy of a dipole in a uniform electric field.
  • Gauss Theorem and applications
  • Metre bridge experiments, Potentiometer principle and experiments
  • Ampere’s circuit law and applications
  • MCG and conversion to ammeter and voltmeter
  • Cyclotron
  • LCR series circuit and resonance, expression for resonant frequency, Q factor, Power factor
  • Optical instruments (complete)
  • Theory of interference, Young’s double slit experiment, expression for fringe width, graph
  • LOGIC Gates (complete)
  • Electromagnetic spectrum, production and uses of em waves
  • Photo electric effect (compete: experimental setup for study of photoelectric effect, conclusions, Einstein’s equation and explanation to laws of PEE.)
  • BE per nucleon vs atomic mass graph and explanation to release of energy during nuclear fission and fusion.
  • CE transistor characteristics and CE transistor amplifier
  • Need for modulation
  • All block diagrams from “Communication”:
  • Total internal reflection and applications

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March 2017

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