Physics: Waves & Optics Flashcards

What is the definition of a wave?

Answer: A transfer of energy without matter movement

A wave is fundamentally a disturbance that propagates through a medium or space, transferring energy from one point to another. Crucially, this transfer of energy occurs without the net transfer of matter; the particles of the medium oscillate about their equilibrium positions but do not travel along with the wave itself.

What is the relationship between frequency and wavelength in a wave?

Answer: Frequency is inversely proportional to wavelength

For a wave traveling at a constant speed (v), its frequency (f) and wavelength (λ) are inversely proportional, as described by the wave equation v = fλ. This means that if the frequency of a wave increases, its wavelength must decrease, and vice versa, to maintain a constant wave speed.

What is refraction?

Answer: Bending of light due to density change

Refraction is the phenomenon where a wave, such as light, changes direction as it passes from one medium to another. This bending occurs because the wave's speed changes as it enters a medium with a different optical density, causing it to deviate from its original path according to Snell's Law.

What is the main principle behind the Doppler effect?

Answer: Wave frequency changes due to relative motion

The Doppler effect describes the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. When the source and observer move closer, the frequency appears higher, and when they move apart, the frequency appears lower, due to the compression or stretching of the wavefronts.

What does the law of reflection state?

Answer: Angle of incidence equals angle of reflection

The law of reflection states that when a wave, such as light, strikes a surface, the angle at which it hits the surface (angle of incidence) is equal to the angle at which it bounces off (angle of reflection). Both angles are measured with respect to the normal, an imaginary line perpendicular to the surface.

What is interference in waves?

Answer: Two waves combine to form a new pattern

Wave interference occurs when two or more waves superpose, meaning they combine their amplitudes at each point in space. This superposition can result in a new wave pattern with either increased amplitude (constructive interference) or decreased amplitude (destructive interference), depending on their relative phases.

What is diffraction?

Answer: Bending of waves around obstacles

Diffraction is the phenomenon where waves spread out or bend as they pass through an aperture or around the edges of an obstacle. This effect is more pronounced when the wavelength of the wave is comparable to the size of the opening or obstacle, causing the wave to deviate from a straight-line path.

How does the frequency of light affect its color?

Answer: Higher frequency corresponds to violet

The color of visible light is determined by its frequency (or wavelength). Within the visible spectrum, light with higher frequencies corresponds to colors like blue and violet, while light with lower frequencies corresponds to colors like orange and red. Therefore, higher frequency light appears violet.

What is the critical angle in refraction?

Answer: The angle at which total internal reflection occurs

The critical angle is the specific angle of incidence in the denser medium at which the refracted ray travels along the boundary between two media. If the angle of incidence exceeds this critical angle, the light undergoes total internal reflection, meaning it is entirely reflected back into the denser medium rather than refracting out.