Tooth fillings are often made of gold or porcelain because these materials are nonreactive.
b. nonreactive.
To get a uniform field in the central region between the coils, current flows in the same direction in each.
There are two conditions necessary for total internal reflection, which is when light hits the boundary between two mediums and reflects back into its original medium:
Light is about to pass from a more optically dense medium (slower) to a less optically dense medium (faster).
The angle of incidence is greater than the defined critical angle for the two mediums, which is given by:
θ = sin⁻¹(
/
)
Where θ = critical angle,
= refractive index of faster medium,
= refractive index of slower medium.
Choice C gives one of the above necessary conditions.
68 degrees would be the answer