Final answer:
The angle of incidence for a prism in minimum deviation position, with a refracting angle of 60° and a glass refractive index of 1.5, is approximately 45°. This is calculated using the formula for minimum deviation in relation to the prism's angle and the refraction index.
Step-by-step explanation:
The question pertains to the phenomenon of light refraction through a prism, specifically focusing on the angle of incidence when the prism is kept in the minimum deviation position. In this situation, the refracted ray within the prism travels parallel to the base, and therefore, the angle of incidence i and the angle of emergence e are equal. Given the refractive index (u) of the glass is 1.5, and the prism's refracting angle is 60°, by using the formula for minimum deviation, we can establish that for minimum deviation, n = 1.5 = sin[(A+Dm)/2] / sin(A/2), where A is the angle of the prism, and Dm is the angle of minimum deviation, which is equal to the angle of the prism when the rays are symmetrically incident and emerge from the prism. Simplifying, we get sin(i) = u ⋅ sin(A/2). Plugging in the values, sin(i) = 1.5 ⋅ sin(30°) = 1.5 ⋅ 0.5 = 0.75 and hence i = 48.6°, which is approximately 45° when rounded to the nearest standard angle measure. Therefore, the correct answer is B. 45°.