Communication with Light & Sound

Question 1

Which device could a student use to send a spoken message to a friend across the playground?

Accepted Answer

Two tin cans connected by a piece of string

Answer

A pair of sunglasses

Answer

A flashlight that shines a beam of light

Answer

A picture book with colorful pages

Question 2

Fiber‑optic cables transmit information using light waves. Which statement correctly explains how the light waves are kept inside the fiber so that the information can travel long distances?

Accepted Answer

The light waves are repeatedly reflected at the boundary between the core and cladding because the core has a higher index of refraction, causing total internal reflection.

Answer

The light waves continuously refract into the cladding, bending away from the core and traveling along the outer surface of the cable.

Answer

The light waves are scattered by impurities in the core, which redirects them forward along the length of the fiber.

Answer

The light waves are absorbed by the cladding, which then re‑emits the light into the core, allowing the signal to continue.

Question 3

Which of these devices could a student use to send a sound message to a friend who is standing far away?

Accepted Answer

Two cups connected by a tight string

Answer

Two paper plates glued together

Answer

A flashlight turned on and off

Answer

A rock placed on the ground

Try three questions

Which device could a student use to send a spoken message to a friend across the playground?

Fiber‑optic cables transmit information using light waves. Which statement correctly explains how the light waves are kept inside the fiber so that the information can travel long distances?

Which of these devices could a student use to send a sound message to a friend who is standing far away?

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