Massachusetts Comprehensive Assessment System

2019, High School Intro Physics

Question 12: Open-Response

Reporting Category: Waves and Radiation
Standard: 4.1 - Describe the measurable properties of waves (velocity, frequency, wavelength, amplitude, and period) and explain the relationships among them. Recognize examples of simple harmonic motion.
Standard: Sci.HS.PHY.4.01 - Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling within various media. Recognize that electromagnetic waves can travel through empty space (without a medium) as compared to mechanical waves that require a medium. Clarification Statements: Emphasis is on relationships when waves travel within a medium, and comparisons when a wave travels in different media. Examples of situations to consider could include electromagnetic radiation traveling in a vacuum and glass, sound waves traveling through air and water, and seismic waves traveling through the Earth. Relationships include v = λf, T = 1/f, and the qualitative comparison of the speed of a transverse (including electromagnetic) or longitudinal mechanical wave in a solid, liquid, gas, or vacuum. State Assessment Boundary: Transitions between two media are not expected in state assessment.

The diagram below represents one type of wave created on a guitar string when the string is plucked. The string has a length of 0.65 m and vibrates at a frequency of 880 Hz.

In your Student Answer Booklet, copy the wave diagram and label the wavelength of the wave.
Calculate the velocity of this wave on the string. Show your calculations and include units in your answer.

The wave on the guitar string also creates sound waves in the air. The speed of the sound waves is 340 m/s in air. The pitch created by the guitar string matches the pitch heard by an observer.

Compare the frequency and wavelength of the wave on the guitar string to the frequency and wavelength of the sound waves in the air.

Scoring Guide for Idea Development

Select a score point in the table below to view the sample student response.

Score	Description
4	The response demonstrates a thorough understanding of the measurable properties of waves (velocity, frequency, wavelength) and the relationships among them. The response correctly labels the wavelength of the wave. The response correctly calculates the velocity of the wave on the guitar string, and correctly compares the frequency and wavelength of the wave on the guitar string to the frequency and wavelength of the sound wave in the air.
4
3	The response demonstrates a general understanding of the measurable properties of waves (velocity, frequency, wavelength) and the relationships among them.
2	The response demonstrates a limited understanding of the measurable properties of waves (velocity, frequency, wavelength) and the relationships among them.
1	The response demonstrates a minimal understanding of the measurable properties of waves (velocity, frequency, wavelength) and the relationships among them.
0	The response is incorrect or contains some correct work that is irrelevant to the skill or concept being measured.

Note: There are 2 sample student responses for Score Point 4.

High School Intro Physics

Question 12: Waves and Radiation

Question 23: Motion and Forces

Question 32: Motion and Forces

Question 44: Heat and Heat Transfer

Question 45: Electromagnetism

Return to the MCAS 2019 Student Work Directory

Last Updated: May 5, 2020