3.3 Particles of Light: Quantum Theory

Question 1

Objects that emit electromagnetic radiation only in integral multiples of an elementary unit

Answer 1

Quantum

Question 2

Planck’s Constant

Answer 2

6.626 x 10^-34 J·s

Question 3

The proportionality between the energy and frequency of electromagnetic radiation.

Answer 3

Planck’s Constant

Question 4

Match the observed colors corresponding to the temperature of the radiation given off by the thermal radiator.

White

Red

Orange

Answer 4

A. Orange

B. White

C. Red

Question 5

Which of the waves has the lowest energy?

Answer 5

D.

Question 6

What is the maximum wavelength, in nm, of light that can eject an electron from a metal with Φ =2.00 x 10–19 J?

Answer 6

Arranging the equation to solve for wavelength.

Φ =(h•c)/ λ

λ = (h•c)/Φ

= ((6.626 x 10^-34 J•s) x (2.998 x 10⁸ m/s)) / (2.00 x 10^-19 J)

= 9.93 x 10^-7m

Then convert to nm

= 9.93 x 10^-7m x 10⁹nm

=9.93 x 10²nm

Question 7

Considered the father of quantum physics and won the 1918 Nobel Prize in Physics for his pioneering work on the quantized nature of electromagnetic radiation.

Answer 7

Max Karl Ernst Ludwig Planck

Question 8

The equation for energy.

Answer 8

E = hv , where h is Planck’s constant and v is the frequency

E= hc/λ, where c is the speed of light

Question 9

Model of matter and energy based on the principle that energy is absorbed or emitted in discrete packets, or quanta.

Answer 9

Quantum Theory

Question 10

Tiny packets or radiant energy that represent elementary building blocks of electromagnetic radition

Answer 10

Photons

Question 11

What is the energy of one photon of light from the largest quantum dot, the one with a wavelength of 640 nm (6.40 ✕ 102 nm)? What is the energy of one mole of those photons?

Answer 11

Using E= hc/λ

((6.626 x 10-34 J•s) x (2.998 x 108 m/s)) / (6.40x 10² nm x 10^-9)

3.10 x 10^-19J

Question 12

6.022 x 10²³ photons

Answer 12

1 mol

Question 13

Brought the view that light was a wave into question, as many metals emitted electrons when light was shined upon them.

Answer 13

Photoelectric Effect

Question 14

Occurs when electrons are ejected from the surface of a metal, when light shines on it.

Answer 14

Photoelectric Effect

Question 15

The minimum frequency of light required to produce the photoelectric effect

Answer 15

Threshold Frequency

Question 16

Proposed that every photoelectric material has a characteristic threshold frequency, ν0, associated with the minimum quantum of absorbed energy needed to remove a single electron from the material’s surface.

Answer 16

Einstein

Question 17

The amount of energy needed to dislodge an electron from the surface of a material.

Answer 17

Work Function

Question 18

The work function of silver is 7.59 ✕ 10^-19 J. What is the longest wavelength (in nanometers) of electromagnetic radiation that can eject a photoelectron from the surface piece of silver?

Answer 18

Using Φ =(hv)

7.59 x 10^-19J = (6.626 x 10^-34J) v

v = 1.14 x 10¹⁵

λ = c/v

(2.998 x 10⁸) / (1.14 x 10¹⁵)

= 2.63 x 10^-7m