MISA Waves and Electromagnetic Radiation 2 — Questions and Answers
Question 1: What does the amplitude of a wave represent?
- The number of wave cycles per second
- The distance between two consecutive crests
- The maximum displacement of the medium from its resting position (Correct answer)
- The speed at which the wave travels
Correct answer: The maximum displacement of the medium from its resting position
Amplitude is the maximum displacement of particles in the medium from their equilibrium position, and it is related to the energy carried by the wave.
Question 2: What is refraction?
- The bouncing of a wave off a surface
- The bending of a wave as it passes from one medium into another (Correct answer)
- The spreading of a wave around an obstacle
- The combination of two waves to form a new wave
Correct answer: The bending of a wave as it passes from one medium into another
Refraction is the bending of a wave's path that occurs when it crosses a boundary between two media with different wave speeds.
Question 3: A wave completes 50 cycles in one second. What is its frequency?
- 50 meters
- 0.02 seconds
- 50 hertz (Correct answer)
- 50 meters per second
Correct answer: 50 hertz
Frequency is the number of complete wave cycles per second, measured in hertz (Hz); 50 cycles per second equals 50 Hz.
Question 4: Which part of the electromagnetic spectrum is used in microwave ovens to heat food?
- Infrared radiation
- Microwaves (Correct answer)
- Radio waves
- Ultraviolet radiation
Correct answer: Microwaves
Microwave ovens use microwaves (typically at 2.45 GHz) because water molecules in food efficiently absorb this frequency and convert it to thermal energy.
Question 5: What phenomenon explains why the sky appears blue on a clear day?
- Refraction of sunlight by atmospheric water vapor
- Reflection of ocean light off clouds
- Scattering of shorter-wavelength blue light by atmospheric gas molecules (Correct answer)
- Absorption of red light by ozone in the stratosphere
Correct answer: Scattering of shorter-wavelength blue light by atmospheric gas molecules
Rayleigh scattering causes shorter-wavelength blue light to be scattered much more strongly by atmospheric nitrogen and oxygen molecules than other colors, making the sky appear blue.
Question 6: When two waves overlap and their crests align, the result is called:
- Destructive interference
- Refraction
- Constructive interference (Correct answer)
- Diffraction
Correct answer: Constructive interference
Constructive interference occurs when two waves combine with their crests (and troughs) aligned, producing a wave with greater amplitude.
Question 7: How do radio waves and visible light differ?
- Radio waves require a medium to travel; visible light does not
- Radio waves travel faster than visible light in a vacuum
- Radio waves have much longer wavelengths and lower frequencies than visible light (Correct answer)
- Radio waves carry more energy per photon than visible light
Correct answer: Radio waves have much longer wavelengths and lower frequencies than visible light
Radio waves have wavelengths ranging from millimeters to kilometers and much lower frequencies than visible light, placing them at the opposite end of the electromagnetic spectrum.
MISA Waves and Electromagnetic Radiation 2
What does the amplitude of a wave represent?