Wireless Speaker Post-Assessment (Review Activity)

How does the total amount of information differ between an analog and a digital signal?

• A digital signal has more information because it has more values than an analog signal

• A digital signal has more information because it has fewer values than an analog signal.

• An analog signal has more information because it has more values than a digital signal.

• An analog signal has more information because it has fewer values than a digital signal.

Answer explanation

A digital signal can represent a wide range of values through discrete levels, allowing for more precise information encoding compared to an analog signal, which is continuous and has infinite values. Thus, the correct choice is that a digital signal has more information.

Why do most modern devices use digital signals?

• Digital signals contain more information than analog signals.

• Digital signals are more reliable over long distances than analog signals.

• Analog signals contain more information than digital signals.

• Analog signals are more reliable over long distances than digital signals.

Answer explanation

Digital signals are less susceptible to noise and degradation over long distances compared to analog signals, making them more reliable for communication in modern devices.

A transmitter on the moon emits sound and light waves to a receiver on Earth. The light waves are picked up by the receiver but sound waves are not. This happens because _________________

• The atmosphere absorbs sound.

• Sound cannot travel through the vacuum.

• Sound gets scattered before it reaches Earth.

• Sound takes a very long time to cover the distance.

Answer explanation

Sound cannot travel through the vacuum of space, which is why the receiver on Earth picks up the light waves but not the sound waves emitted by the transmitter on the moon.

Read each description below and decide if light is being mostly absorbed or reflected. Category 1: Mostly absorbed Category 2: Mostly reflected A. A white light is shined onto a black shirt B. A red light is shined onto a ripe strawberry. C. A dark towel heats up after being left in the sun. D. A shoe sits out in the sun with very little increase in temperature.

• A. Category 1: Mostly absorbed B. Category 2: Mostly reflected C. Category 1: Mostly absorbed D. Category 2: Mostly reflected

• A. Category 2: Mostly reflected B. Category 1: Mostly absorbed C. Category 2: Mostly reflected D. Category 1: Mostly absorbed

• A. Category 2: Mostly reflected B. Category 2: Mostly reflected C. Category 1: Mostly absorbed D. Category 1: Mostly absorbed

• A. Category 1: Mostly absorbed B. Category 1: Mostly absorbed C. Category 2: Mostly reflected D. Category 2: Mostly reflected

Answer explanation

A. Black absorbs most light. B. Strawberry reflects red light. C. Dark towel absorbs heat. D. Shoe reflects light, staying cool. Thus, A and C are mostly absorbed, while B and D are mostly reflected.

Which part of the longitudinal wave shown above represents one wavelength?

• Part A

• Part B

• Part C

• Part D

Answer explanation

Part D represents one complete wavelength in a longitudinal wave, as it includes one compression and one rarefaction. This is the standard definition of a wavelength in such waves.

The diagram above shows a triangular wave. Which lettered part represents the amplitude of the wave?

• Part A

• Part B

• Part C

• Part D

Answer explanation

The amplitude of a wave is the maximum height from the rest position to the peak. In the diagram, Part B represents this height, indicating the amplitude of the triangular wave.

Plucking a guitar string creates a wave whose motion is perpendicular to the downward force on the strings. The movement of the string is an example of a _____________.

• Longitudinal wave

• Microwave

• Light wave

• Transverse wave

Answer explanation

The movement of the guitar string is perpendicular to the force applied, which characterizes a transverse wave. In transverse waves, the oscillation direction is at right angles to the wave's direction of travel, making 'transverse wave' the correct choice.

Select the phrases below that are characteristics of sound waves. (NOTE: select more than one answer.)

• B. Always travels at the same speed

• F. Travels faster in solids than through air.

• C. Causes molecules to increase in size

• D. Can travel through any type of matter

• A. Can cause objects to vibrate

Answer explanation

Sound waves travel faster in solids than in air (F), can move through any matter (D), and cause objects to vibrate (A). The other options do not accurately describe sound wave characteristics.

Which material reflects the most light?

• Wax paper

• Aluminum foil

• Plastic wrap

• Brown paper

Answer explanation

Aluminum foil reflects the most light due to its shiny, metallic surface, which is designed to minimize light absorption. In contrast, wax paper, plastic wrap, and brown paper are less reflective.

When a musician blows into a trumpet, a sound wave is formed that moves in the same direction as the musician’s breath. This is an example of a

• Microwave

• Light wave

• Longitudinal wave

• Transverse wave

Answer explanation

When a musician blows into a trumpet, the sound wave travels in the same direction as the breath, indicating that the particles of the medium (air) move parallel to the wave direction. This is characteristic of a longitudinal wave.