Explanation
Comets do not revolve around the sun in fixed elliptical orbit like other planets and don’t obey Kepler’s law for planetary motion.
Red shift means that wavelength of light received from stars is increasing i.e., apparent frequency is decreasing. Therefore, the stars/galaxies must be receding away. Hence the universe is expanding.
Reason is also true, but it does not explain the assertion appropriately.
Both the Assertion and Reason are true and Reason is a correct explanation of the Assertion.
The assertion is not true. Infact, the value of Hubble’s constant is 16 km per sec per million light years.
O type stars are hottest.
Tail of comet points away from the sun.
The number of stars in our solar system in one (our Sun.)
Radio waves can be transmitted from one place to another as grand wave or sky wave or space wave propagation.
A very small part of light energy is lost from an optical fibre due to absorption or due to light leaving the fibre as a result of scattering of light sideways by impurities in the glass fibre.
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