NCERT Class 10 Science — Chapter 2: The Human Eye and the Colourful World

The correct Answer is Angle of the prism

Explanation

The question pertains to the terminology used in optics, specifically concerning the geometry of a triangular prism. A prism is a transparent optical element with flat, polished surfaces that refract light.

Statement-wise Analysis

The question asks for the term describing the angle between the two lateral faces of a triangular prism. Angle of deviation Incorrect. The angle of deviation is the angle between the incident ray and the emergent ray when light passes through a prism. It is not an intrinsic property of the prism's geometry. Angle of the prism Correct. The angle of the prism, also known as the refracting angle or apical angle, is defined as the angle between the two refracting surfaces (lateral faces) of the prism. This angle determines how much the light ray will deviate. Angle of refraction Incorrect. The angle of refraction is the angle between the refracted ray and the normal to the surface at the point of refraction. It is an angle associated with the light ray's path, not the prism's physical structure. Angle of incidence Incorrect. The angle of incidence is the angle between the incident ray and the normal to the surface at the point where the light ray strikes the surface. It is an angle associated with the light ray's path, not the prism's physical structure.

Key Takeaway

The angle between the two lateral faces of a triangular prism is termed the angle of the prism or refracting angle.