- Compressions and rarefactions are characteristic of a longitudinal waves b, transverse waves c. both of these. d. neither of these. 36. A plane mirror will produce a virtual image (A) when the object distance is greater than the image distance. (B) when the object distance is less than the image distance. (C) when the object is on the principal axis of the mirror. (D) when the rays converge at the focal point of the mirror (E) at all distances from the mirror. 37. Wave interference can occur for a. sound waves. b. light waves. c. water waves d. all of these. e. none of these. 38. In a longitudinal wave, the compressions and rarefactions travel in a. the same direction that the wave travels. b, a direction opposite to the wave travel. c. neither. 39. The fundamental frequency of a violin string is 440 Hz. The frequency of an octave is A. 220 Hz B. 440 Hz C 880 Hz D. none of the above Amplitude 40. The amplitude of a particular wave is 1 m. The top to bottom (crest to trough) distance of the wave is d. none of these.
The Correct Answer and Explanation is :
Let’s break down each question and provide the correct answers with explanations:
35. Compressions and rarefactions are characteristic of:
- Answer: a. longitudinal waves
- Explanation: Compressions and rarefactions are characteristics of longitudinal waves. In longitudinal waves, particles of the medium move parallel to the direction of wave propagation. A compression is a region where particles are closer together, while a rarefaction is a region where particles are spread apart. Sound waves are a common example of longitudinal waves.
36. A plane mirror will produce a virtual image:
- Answer: E. at all distances from the mirror
- Explanation: A plane mirror always forms a virtual image, regardless of the object’s distance from the mirror. The image appears to be behind the mirror and is upright, of the same size as the object, and laterally reversed. Virtual images formed by plane mirrors cannot be projected onto a screen, as the light rays do not actually converge.
37. Wave interference can occur for:
- Answer: d. all of these
- Explanation: Wave interference can occur for sound waves, light waves, and water waves. Interference happens when two or more waves meet at the same point, resulting in a new wave pattern. The two main types of interference are constructive interference (where the waves combine to form a larger wave) and destructive interference (where the waves cancel each other out). This phenomenon is observed in sound, light, and water waves.
38. In a longitudinal wave, the compressions and rarefactions travel in:
- Answer: a. the same direction that the wave travels
- Explanation: In a longitudinal wave, compressions and rarefactions propagate in the same direction that the wave moves. The particles in the medium oscillate back and forth in the direction of wave propagation. This is different from transverse waves, where particles move perpendicular to the direction of wave propagation.
39. The fundamental frequency of a violin string is 440 Hz. The frequency of an octave is:
- Answer: C. 880 Hz
- Explanation: An octave corresponds to a doubling of frequency. So, if the fundamental frequency of a violin string is 440 Hz, the frequency of the note one octave higher will be 880 Hz. This is because the frequency doubles for each octave. The relationship between frequencies in octaves is logarithmic.
40. The amplitude of a particular wave is 1 m. The top-to-bottom (crest-to-trough) distance of the wave is:
- Answer: 2 m
- Explanation: The amplitude of a wave is the maximum displacement of the wave from its equilibrium position. The top-to-bottom (crest-to-trough) distance is the full vertical distance between the highest point (crest) and the lowest point (trough) of the wave. Since the amplitude is 1 m, the total distance between the crest and trough is twice the amplitude, which is 2 meters.
These explanations address the concepts of wave behavior and image formation, providing insight into the nature of waves, frequencies, and mirror images.