Answer:
but for helping we need yr ques nd they r not here
Answer:

Explanation:
Frequency of each electromagnetic wave is same thus we can interfere them along X axis in Phase diagram.
In phase diagram indicate each wave as vector with amplitude as length and phase difference as angle. (shown in attachment)
Now take component of E2 and E3 amplitude along X direction.
Net amplitude of all E in X direction =
+ cos(45)[
+
]
⇒
Final resultant have no change in frequency
So , resultant is 
Answer:
θ₂ = 35.26°
Explanation:
given,
refractive index of air, n₁ = 1
refractive index of glass, n₂ = 1.5
angle of incidence, θ₁ = 60°
angle of refracted light, θ₂ = ?
using Snell's Law
n₁ sin θ₁ = n₂ sin θ₂
1 x sin 60° = 1.5 sin θ₂
sin θ₂ = 0.577
θ₂ = sin⁻¹(0.577)
θ₂ = 35.26°
Hence, the refracted light is equal to θ₂ = 35.26°
The answer is false
Thats my far estimation
Answer: The correct answer is : From the period-luminosity relation for Cepheids, he was able to determine the distance to Andromeda and show that it was far outside the Milky Way Galaxy.
Explanation: Hubble's law says that the recession velocity of a galaxy is directly proportional to its distance from us. Hubble measured the distance to the Andromeda galaxy by applying the period-luminosity relationship to Cepheid.