It would be B. Because every angle has to add up to 180 degrees. 180-70 would give you 110
Index of refraction can be calculated using the following formula:

where
in a vacuum and "n" is the index of refraction. So we must calculate our velocity by manipulating the index of refraction formula and isolate v and so:

We could go one by one and calculate the velocity or use logic. If you divide by a larger number the output will be a smaller number. Therefore, the answer would be n=1.62 is the slowest.

By that logic when n=1 light would travel the fastest of these four scenarios. The key thing to understand about these problems is that the speed of light slows down as it goes through a medium, in a vacuum it's 3 x 10^ 8 m/s but as it goes through say air or water light slows down.
The magnitude of the magnetic field on the axis of the ring 5 cm from its center is 143 pT.
The radius of the nonconducting ring is R = 10 cm.
The ring is uniformly charged q = 10 μC.
The angular speed of the ring, ω = 20 rad/s
The ring is x = 5 cm from the center of the ring.
Now,
R = 10 cm = 0.1 m
q = 10.0 μC = 10 × 10⁻⁶ C
x = 5 cm = 0.05 m
The magnetic field on the axis of a current loop is given as:
B = [ μ₀ IR² ] / [4π(x² + R²)^{3/2} ]
Now, I = q / [2π/ω]
So, the magnitude of the magnetic field which is directed away from the center is:
B = [ μ₀ ωqR² ] / [4π(x² + R²)^{3/2} ]
B = [ μ₀ (200) (10 × 10⁻⁶) (0.1)² ] / [4π((0.05)² + (0.1)²)^{3/2} ]
B = 1.43 × 10⁻¹⁰ T
B = 143 pT
Learn more about the magnetic field here:
brainly.com/question/14411049
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C is the answer
hope it helped!
DIAMONDS are NOT rocks. Diamonds are minerals, rocks are made up of many different fragments of minerals.