BMST Waves, Sound, and Light 1 โ Questions and Answers
Question 1: What is the approximate speed of light in a vacuum?
- 3 ร 10โธ m/s (Correct answer)
- 3 ร 10โถ m/s
- 3 ร 10ยนโฐ m/s
- 3 ร 10โด m/s
Correct answer: 3 ร 10โธ m/s
The speed of light in a vacuum is approximately 3 ร 10โธ meters per second (about 300,000 km/s).
Question 2: What type of wave is sound?
- Transverse wave
- Longitudinal wave (Correct answer)
- Electromagnetic wave
- Surface wave
Correct answer: Longitudinal wave
Sound is a longitudinal wave because the particles of the medium vibrate parallel to the direction of wave travel, creating compressions and rarefactions.
Question 3: What is the relationship between frequency and wavelength for a wave traveling at constant speed?
- They are directly proportional
- They are inversely proportional (Correct answer)
- They are always equal
- They are unrelated
Correct answer: They are inversely proportional
Since wave speed = frequency ร wavelength, at constant speed, frequency and wavelength are inversely proportional โ as one increases, the other decreases.
Question 4: When a light ray bounces off a surface at the same angle it hit, what phenomenon is occurring?
- Refraction
- Diffraction
- Reflection (Correct answer)
- Absorption
Correct answer: Reflection
Reflection occurs when a wave bounces off a surface, following the law that the angle of incidence equals the angle of reflection.
Question 5: What is the unit of frequency?
- Meter (m)
- Second (s)
- Hertz (Hz) (Correct answer)
- Watt (W)
Correct answer: Hertz (Hz)
Frequency is measured in Hertz (Hz), which represents the number of complete wave cycles per second.
Question 6: If the frequency of a sound wave increases, what happens to the pitch heard by a listener?
- Pitch decreases
- Pitch increases (Correct answer)
- Pitch stays the same
- Pitch becomes inaudible
Correct answer: Pitch increases
Higher frequency sound waves produce higher pitched sounds because more vibrations per second correspond to a higher musical tone.
Question 7: What is the bending of light as it passes from one medium into another medium called?
- Reflection
- Diffraction
- Polarization
- Refraction (Correct answer)
Correct answer: Refraction
Refraction is the bending of light when it passes from one medium to another due to a change in wave speed at the boundary.
BMST Waves, Sound, and Light 1
What is the approximate speed of light in a vacuum?