Waves and Electromagnetic Radiation Flashcards

What is diffraction?

Answer: The spreading of waves as they pass through an opening or around an obstacle

Diffraction is the bending and spreading of waves when they encounter an opening or obstacle, and it is most pronounced when the opening is comparable in size to the wavelength.

The Doppler effect describes:

Answer: The apparent change in frequency of a wave due to relative motion between the source and observer

The Doppler effect is the perceived shift in frequency (and therefore pitch or color) of a wave when the source and observer are moving relative to each other.

What is the period of a wave?

Answer: The time required to complete one full wave cycle

The period (T) is the time it takes for one complete wave cycle to pass a given point; it is the reciprocal of frequency (T = 1/f).

Which type of electromagnetic radiation is used in medical imaging to view bones inside the body?

Answer: X-rays

X-rays have enough energy to penetrate soft tissue but are absorbed by denser bone, making them ideal for diagnostic medical imaging.

A wave has a frequency of 200 Hz and a speed of 400 m/s. What is its wavelength?

Answer: 2 m

Using the wave equation λ = v/f, the wavelength equals 400 m/s ÷ 200 Hz = 2 m.

Ultraviolet (UV) radiation from the Sun can cause sunburn because it:

Answer: Has higher frequency than visible light and carries enough energy to damage skin cells

UV radiation has higher frequency and more energy per photon than visible light, giving it enough energy to break chemical bonds and damage DNA in skin cells.

Which statement best explains why electromagnetic waves can travel through the vacuum of space but sound waves cannot?

Answer: Electromagnetic waves are self-propagating disturbances in electric and magnetic fields and need no medium, whereas sound waves require matter to transmit compressions

Electromagnetic waves are oscillating electric and magnetic fields that sustain each other as they travel, requiring no material medium, while sound waves are pressure disturbances that need matter (particles) to propagate.