Quantum ideas and where they are used

Answer Key - Grade 11 Science Worksheet - Building Confidence

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

1. 1.

   This LED's energy gap is 2.3 eV. With hc = 1239.84 eV·nm, what wavelength of light does it give out, to the nearest nm, Bo?

   539 nm
2. 2.

   This LED's energy gap is 2.8 eV. With hc = 1239.84 eV·nm, what wavelength of light does it give out, to the nearest nm, Esme?

   443 nm

3. Read this first

   Use this

   Photon diagram beside a short passage: "In an LED, electrons drop across an energy gap and give out photons. Each photon's energy equals the gap. A gap of 2.3 eV gives green light near 539 nm; a wider gap gives bluer light."

5. 3.

   In the passage, what makes an LED give out light, Jun?

   • Heat from a thin wire glowing inside
   • Electrons dropping across a gap
   • Sound inside the LED
6. 4.

   In the passage, how would an LED with a wider gap look, Kira?

   Use the picture in question 3.

   • Bluer
   • The same color, but brighter
   • Redder
7. 5.

   In the passage, what sets each photon's energy, Luz?

   Use the picture in question 3.

   • The LED's brightness
   • The battery's size
   • The size of the gap
8. 6.

   What is special about laser light, Milo?

   • One color, with its waves in step
   • It is made of sound
   • It mixes many colors
9. 7.

   How does a solar cell make a current, Noah?

   • Heat melts its wires
   • It stores sunlight as charge
   • Photons free electrons in it
10. 8.

    What does an MRI scanner use to make pictures, Pia?

    • A strong magnet and radio waves
    • Sound waves
    • X-rays passing through the body
11. 9.

    In physics, what is a quantum, Ren?

    • The smallest step an amount can change by
    • A very large, sudden jump in energy or size
    • A kind of magnet
12. 10.

    What is one quantum of light called, Tala?

    • A huge burst of light
    • An electron
    • A photon