Sound, EM waves and Digital vs. Analogue signals

In a longitudinal wave, which region corresponds to the maximum particle concentration?

• Compression

• Rarefaction

• Both are equal

• Neither one shows particle concentration

Which statement is true regarding electromagnetic waves in a vacuum?

• Only visible light travels at speed 𝑐.

• Only radio waves travel at speed 𝑐.

• All regions of the electromagnetic spectrum travel at speed 𝑐.

• Only high-energy waves travel at speed 𝑐.

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Electromagnetic waves travel through air at approximately:

• 1.00 × 10⁸ m/s

• 3.00 × 10⁸ m/s

• 5.00 × 10⁸ m/s

• 9.00 × 10⁸ m/s

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NGSS.HS-PS4-1

Which of the following are uses of radio waves?

• Radio and television transmissions

• Astronomy for detecting cosmic signals

• Radio Frequency Identification (RFID)

• Medical X‑ray imaging

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In radio communication, information is transmitted by modulating certain properties of the wave. Which parameters are typically modulated?

• Frequency

• Amplitude

• Color

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Which of the following applications make use of microwaves?

• Satellite communications

• Mobile phones and WiFi

• Microwave ovens

• Infrared cameras

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Which of the following are common applications of infrared waves?

• Electric grills

• Remote controllers for televisions

• Optical fibers for high-speed broadband

• X‑ray imaging

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Visible light is used in several everyday applications. Which of the following are among its uses?

• Optic fibers

• Illumination

• Photography

• Vision

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Which of the following are applications of ultraviolet (UV) radiation?

• Security marking

• Detecting fake bank notes

• Sterilizing water

• Enhancing night vision

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Excessive exposure to UV radiation can lead to which harmful effects?

• Damage to surface cells

• Eye conditions

• Skin cancer

• Enhanced immune response