Long Q/A Geometrical Optics

Differentiate between real and virtual images. What are three basic rays by which we can draw a ray diagram to form an image by a spherical mirror?

Real Image: Formed by actual convergence of rays; can be projected on a screen; inverted. Virtual Image: Formed by apparent divergence of rays; cannot be projected on a screen; erect. Basic rays for ray diagrams: 1. A ray parallel to the principal axis passes through the focus after reflection. 2. A ray passing through the … Read more

What is the spherical mirror formula? Also, write down the sign conventions for the spherical mirror formula.

The spherical mirror formula relates the focal length fff, the object distance uuu, and the image distance vvv for a spherical mirror (concave or convex mirror). The formula is given as: 1/f=1/v+1/υ​ Definitions: f: Focal length of the mirror v: Image distance (distance from the mirror to the image) υ: Object distance (distance from the … Read more

Define the principal focus of convex and concave mirrors. Define focal length. Which mirror has a positive focal length? Which has a negative focal length and why?

Principal focus: The point where parallel rays meet or appear to diverge after reflection. Focal length (f): The distance between the pole (P) and focus (F). Positive focal length: A convex mirror has a positive focal length because its focus is behind the mirror. Negative focal length: A concave mirror has a negative focal length … Read more

Why is a concave mirror called a converging mirror? Why is a convex mirror called a diverging mirror?

A concave mirror converges parallel rays to a single focus, so it is called a converging mirror. A convex mirror spreads parallel rays outward, making them appear to come from a virtual focus, so it is called a diverging mirror.   Related Questions: What is reflection of light? Define the following terms: Incident ray, reflected … Read more

What are different spherical mirrors? Define different terms involved in spherical mirrors.

A spherical mirror is a mirror that has the shape of a piece cut out of a spherical surface. There are two types of spherical mirrors: concave mirror and convex mirror. Types of Spherical Mirrors: 1. Concave mirror (converging mirror) 2. Convex mirror (diverging mirror) Terms in Spherical Mirrors: Pole (P): The center of the mirror … Read more

What is reflection of light? Define the following terms: Incident ray, reflected ray, normal, angle of incidence, and angle of reflection. Describe the laws of reflection.

Reflection of light is the bouncing back of light when it strikes a smooth surface. Incident ray: The incoming ray that strikes the surface. Reflected ray: The outgoing ray after reflection. Normal: A perpendicular line drawn at the point of incidence. Angle of incidence (i): The angle between the incident ray and the normal. Angle … Read more