Answer:
Different star constellations are visible from Earth at different seasons of the year.
Explanation:
The reason the fact that we can see different constellations in the sky during different seasons on earth is the most compelling reason we travel around the sun is because if the sun travelled around the earth, certain constellations would only be visible in certain places. You’d have to travel to see certain ones.
However, you don’t have to do that because we travel around the sun, therefore travelling around other stars too.
Spring potential energy:
E = 0.5 * k * x²
k spring constant
x spring compression
x = √(2 * E / k) = 0.7
Answer:
Option C. be frozen at 12 noon
Explanation:
This can be explained by the special theory of relativity according to which at greater speeds time slows down and length contracts in the direction of motion.
Also if a body travels at the speed of light time will stop and the body will will reduce to zero length.
Therefore, for the given case time will freeze at 12 noon.
Answer:

Explanation:
f = Frequency = 75 Hz
B = Magnetic field = 
d = Diameter of cell = 
t = Time taken
= Angular frequency
The expression of emf is

Emf is maximum when
and N = number of turns = 1

The maximum emf that can be generated around the perimeter of a cell in this field is 
Answer: If a star's radial velocity is -50 km/s, the frequency of its light would appear to be higher than its true frequency. We usually say that the star's wavelength is blue shifted.
Explanation:
Radial velocity is defined as the velocity of how an object is seen by the axis of a circle.
Then, if the radial velocity is -50km/s, this means that the radius is decreasing, and then that the star is coming towards the viewer.
as the star is coming towards the viewer, we will see a shorter wavelength, which implies that the frequency would appear to be bigger as it really is.
and this is called a blue shift, because the blue light is the visible light with the biggest frequency, while the red light is the visible light with the smallest frequency, then we have:
If a star's radial velocity is -50 km/s, the frequency of its light would appear to be higher than its true frequency. We usually say that the star's wavelength is blue shifted.