Light- Reflection and Refraction

This set of vocabulary flashcards covers fundamental concepts of light, mirroring laws, image characteristics, spherical mirror and lens properties, and associated mathematical formulas.

Luminous objects

Objects that emit light of their own, such as the sun, lamps, and candles.

Non-luminous objects

Objects like tables and chairs that do not emit light of their own but are visible because they reflect light from luminous objects.

Light rays

Electromagnetic waves that do not require any material medium for their propagation.

Reflection of light

The process of sending back light rays which fall on the surface of an object.

Silver metal

Regarded as one of the best reflectors of light.

Ray of light

The straight line along which the light traveled.

Beam of light

A bundle of light rays.

Laws of Reflection

1. The angle of incidence is equal to the angle of reflection. 2. The incident ray, reflected ray, and the normal at the point of incidence all lie in the same plane.

Real Images

Images formed when rays of light meet at a point after reflection or refraction; they can be formed on a screen.

Virtual images

Images formed when outgoing rays do not actually meet but appear to meet at a point; they cannot be formed on a screen.

Lateral inversion

The phenomenon where the right side of an object appears as the left side of its mirror image, and the left side appears as the right side.

Concave mirror

A spherical mirror where the reflection of light takes place at the concave or bent-in surface.

Convex mirror

A spherical mirror where the reflection of light takes place at the convex or bent-out surface.

Center of curvature

The center of the sphere of which the reflecting surface of a spherical mirror forms a part; represented by the letter $C$.

Radius of curvature

The radius of the sphere of which the reflecting surface of a spherical mirror forms a part; represented by the letter $R$. It relates to focal length by $R = 2f$.

Pole

The center of a spherical mirror, represented by the letter $P$.

Principal axis

The straight line passing through the pole and the center of curvature of a spherical mirror or a lens.

Aperture

The portion of a mirror or lens from which the reflection or refraction of light actually takes place, representing its size.

Principal focus

The point on the principal axis where rays parallel to the axis intersect or appear to come from after reflection or refraction; represented by the letter $F$.

Focal length

The distance between the pole and the principal focus of a spherical mirror (or optical center and focus of a lens); represented by the letter $f$.

Mirror formula

The mathematical relationship between image distance ($v$), object distance ($u$), and focal length ($f$) for a mirror: $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$.

Magnification (m)

The ratio of the height of the image to the height of the object; for mirrors it is also given by $m = -\frac{v}{u}$.

Refraction of light

The bending of light when it passes from one transparent medium to another due to a change in the speed of light.

Optically rarer medium

A medium in which the speed of light is higher.

Optically denser medium

A medium in which the speed of light is lower, such as glass compared to air.

Snell’s law of refraction

The principle stating that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant: $\frac{ ext{sin}(i)}{ ext{sin}(r)} = ext{constant}$.

Absolute refractive index

The refractive index of a medium considered with respect to a vacuum or air, calculated as $n_m = \frac{c}{v}$.

Convex lens

A converging lens that bulges outward and is thick at the center and thinner at the edges.

Concave lens

A diverging lens that bulges inward and is thinner in the middle and thicker at the edges.

Optical centre

The central point of a lens, represented by the letter $O$, through which light passes without deviation.

Lens Formula

The mathematical relationship for lenses: $\frac{1}{f} = \frac{1}{v} - \frac{1}{u}$, where $v$ is image distance and $u$ is object distance.

Power of a lens

The reciprocal of the focal length of a lens, given by $P = \frac{1}{f}$, where focal length is in meters.

Diopter

The SI unit of power of a lens, denoted as $D$, where $1 D = 1 m^{-1}$.