Concepts Of Physics MCQ Edition [Volume 1]
- Exam
- Concepts Of Physics MCQ Edition [Volume 1]
- Subject
- Physics
- Chapter
- Wave Motion and Waves on a String
Concepts Of Physics MCQ Edition [Volume 1] · Physics · Wave Motion and Waves on a String
Mark out the correct options.
Mark out the correct options.
Options
- AThe energy of any small part of a string remains constant in a travelling wave
- BThe energy of any small part of a string remains constant in a standing wave
- CThe energies of all the small parts of equal length are equal in a travelling wave
- DThe energies of all the small parts of equal length are equal in a standing wave
Correct answer
B. The energy of any small part of a string remains constant in a standing wave
Step-by-step solution
In a travelling wave, energy is continuously transmitted along the string.
The energy of a small part of the string in a travelling wave fluctuates with time, as its kinetic and potential energy densities are maximum at the mean position and zero at the extreme position. Hence, option 1 is incorrect.
Since the energy density is non-uniform at any given instant, all small parts of equal length do not possess equal energies in a travelling wave. Hence, option 3 is incorrect.
In a standing wave, energy is confined within regions and no net energy is transmitted along the string. Each small part of the string executes simple harmonic motion with a fixed amplitude depending on its position.
For a particle executing simple harmonic motion, the total energy is constant. Therefore, the energy of any small part of the string remains constant in a standing wave. Hence, option 2 is correct.
In a standing wave, the amplitude of oscillation varies with position, being zero at the nodes and maximum at the antinodes. Since the total energy of an oscillator depends on the square of its amplitude, small parts of equal length located at different positions will have different energies. Hence, option 4 is incorrect.
The energy of a small part of the string in a travelling wave fluctuates with time, as its kinetic and potential energy densities are maximum at the mean position and zero at the extreme position. Hence, option 1 is incorrect.
Since the energy density is non-uniform at any given instant, all small parts of equal length do not possess equal energies in a travelling wave. Hence, option 3 is incorrect.
In a standing wave, energy is confined within regions and no net energy is transmitted along the string. Each small part of the string executes simple harmonic motion with a fixed amplitude depending on its position.
For a particle executing simple harmonic motion, the total energy is constant. Therefore, the energy of any small part of the string remains constant in a standing wave. Hence, option 2 is correct.
In a standing wave, the amplitude of oscillation varies with position, being zero at the nodes and maximum at the antinodes. Since the total energy of an oscillator depends on the square of its amplitude, small parts of equal length located at different positions will have different energies. Hence, option 4 is incorrect.