Answer:
83.6°
Explanation:
For the ray to be totally internally reflected, at the boundary, the angle of refraction is 90. Using the law of refraction where
n₁sinθ₁ = n₂sinθ₂ where n₁ = refractive index of prism = 1.5, θ₁ = critical angle in prism, n₂ = refractive index of air = 1 and θ₂ = refractive angle = 90°.
So, substituting these values into the equation,
n₁sinθ₁ = n₂sinθ₂
1.5 × sinθ₁ = 1 × sin90
1.5 × sinθ₁ = 1
sinθ₁ = 1/1.5
sinθ₁ = 0.6667
θ₁ = sin*(0.6667)
θ₁ = 41.8°
So, for total internal reflection, an incidence angle of 41.8° is required. So, a full convergence angle of 2 × 41.8° = 83.6° is required for the whole bundle of rays.
Answer:
iv) It is 9x bigger than before
Explanation:
As the amplitudes of the new speakers add directly with the original one, taking into account the phase that they have, the composed amplitude of the sound wave is as follows:
At = A + 4A -2A = 3 A
The intensity of the wave, assuming it propagates evenly in all directions, is constant at a given distance from the source, and can be expressed as follows:
I = P/A
where P= Power of the wave source, A= Area (for a point source, is equal to the surface area of a sphere of radius r, where is r is the distance to the source along a straight line)
For a sinusoidal wave, the power is proportional to the square of the amplitude, so the intensity is proportional to the square of the amplitude also.
If the amplitude changes increasing three times, the change in intensity will be proportional to the square of the change in amplitude, i.e., it will be 9 times bigger.
So, the statement iv) is the right one.
Magnitude of displacement = 
Adding the squares gives displacement = 
Displacement = ≈ 724.7m
