Waves Basics — Set 6
Physics · तरंगों की मूल बातें · Questions 51–60 of 60
Two tuning forks of frequencies 256 Hz and 260 Hz are sounded together. What is the beat frequency?
Correct Answer: D. 4 Hz
Option D is correct because beat frequency equals |f1 − f2| = |256 − 260| = 4 Hz. Beats are slow changes in loudness due to superposition. The closer the frequencies, the slower the beats.
In a standing wave, the distance between a node and the nearest antinode is?
Correct Answer: D. λ/4
λ/4 is correct because nodes and antinodes alternate every quarter wavelength. Node-to-node spacing is λ/2 in a standing wave. Standing waves result from interference of opposite traveling waves.
For a string fixed at both ends, the frequency of the nth harmonic is?
Correct Answer: D. f_n = n(v/2L)
f_n = n(v/2L) is correct because each harmonic fits n half-wavelengths in length L. The fundamental is f1 = v/2L for a fixed string. Harmonics are integer multiples of the fundamental frequency.
A closed organ pipe supports which set of harmonics ideally?
Correct Answer: A. Only odd harmonics
Only odd harmonics are correct because one end is closed and one is open. This boundary condition allows 1st, 3rd, 5th, and so on. An open pipe allows all integer harmonics ideally.
Diffraction is most prominent when the size of the obstacle or opening is?
Correct Answer: B. Comparable to wavelength
Comparable to wavelength is correct because strong bending occurs under that condition. If the opening is much larger than λ, diffraction is weak. This is why sound diffracts more than light in daily life.
What is the relationship between frequency (f) and wavelength (λ) of a wave?
Correct Answer: A. v = f × λ
The fundamental wave equation is v = fλ, where v is velocity, f is frequency, and λ is wavelength. This applies to all types of waves — sound, light, and water waves.
Transverse waves can travel through?
Correct Answer: B. Solids and on liquid surfaces
Transverse waves need rigidity to propagate, so they travel through solids. They can also travel on the surface of liquids (like water waves) but not through the bulk of liquids or gases.
The phenomenon of bending of waves around obstacles is called?
Correct Answer: C. Diffraction
Diffraction is the bending of waves around edges or through small openings. It is more prominent when the size of the obstacle is comparable to the wavelength. This explains why we can hear sounds around corners.
What type of wave is a sound wave?
Correct Answer: D. Longitudinal
Sound waves are longitudinal mechanical waves where particles vibrate parallel to the direction of wave propagation, creating compressions and rarefactions. They need a medium to travel and cannot propagate in vacuum.
The superposition of two waves of slightly different frequencies produces?
Correct Answer: A. Beats
When two sound waves of slightly different frequencies overlap, they produce beats — periodic variations in loudness. The beat frequency equals the difference between the two frequencies.