How devices use waves to send and capture information and energy

Answer Key - Grade 11 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Quartz glass has n = 1.46 (Engineering ToolBox). For light inside it meeting air (n = 1.00), what is the critical angle, to 0.01°, Ari?

   43.23 °
2. 2.

   Diamond has n = 2.417 (Engineering ToolBox). For light inside it meeting air (n = 1.00), what is the critical angle, to 0.01°, Esme?

   24.44 °
3. 3.

   Why does light stay inside a fiber-optic cable as it bends, Jun?

   • The glass soaks up the light and glows
   • The light slows to a stop
   • Total internal reflection at the edge
4. 4.

   How must the cladding around a fiber's core compare with the core, Kira?

   • It must be made of metal
   • It has a lower refractive index
   • It has a higher refractive index
5. 5.

   Why do ultrasound scanners use millions of vibrations per second, Milo?

   • Low pitches can't enter gel
   • High pitches are louder
   • Short waves show fine detail
6. 6.

   Why do internet links between cities use fiber rather than copper wire, Noah?

   • Fiber is heavier and stronger
   • Copper can't carry any electric signals
   • Light carries far more bits each second
7. 7.

   A router offers 2.4 GHz and 5 GHz. Which usually reaches farther through walls, Pia?

   • Both reach equally far
   • 5 GHz, since it is faster
   • 2.4 GHz, with its longer waves
8. 8.

   Ren says ultrasound scanners use X-rays. Agree or disagree?

   • Agree: they use very weak X-rays
   • Agree: echoes are X-rays
   • Disagree: they use sound waves
9. 9.

   Tala says a solar panel turns all the sunlight it gets into electricity. Agree or disagree?

   • Disagree: much becomes heat
   • Agree: panels waste no energy
   • Agree: sunlight is pure electricity
10. 10.

    Zee says Wi-Fi signals are slower than light. Agree or disagree?

    • Disagree: both travel at c
    • Agree: radio waves are slower
    • Agree: walls make them crawl