Physics: An Introduction Chapter 30 -- Practice Questions

Chapter 30: Quantum Physics
Practice Questions

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At what temperature would a body appear red?

1000 K

3000 K

6000 K

10000 K

What is the energy in eV of a microwave photon of wavelength 3 cm?

4.1x10^-5 eV

4.1x10^-3 eV

4.1 eV

410 eV

What is the energy in eV of a red photon of wavelength 750 nm?

4.1x10^-5 eV

1.7 eV

2.9 eV

410 eV

What is the energy in eV of a UV photon of wavelength 300 nm?

4.1x10^-2 eV

4.1 eV

41 eV

410 eV

What is the energy in eV of a X-ray photon of wavelength .3 nm?

4.1x10⁵ eV

4.1x10⁴ eV

4.1x10³ eV

410 eV

How many of the X-ray photons in question 5 must strike a surface in one second to deliver power of 1x10^-12 W?

1524

20000

4x10⁸

How many of the microwave photons in question 2 must strike a surface in one second to deliver power of 1x10^-12 W?

4.1x10⁵

1.5x10⁷

1.5x10

1.5x10¹¹

What wavelength photon would produce an (average) intensity of 1 W/m² with only one photon striking each 1x10^-12 m² of the surface per second?

2 mm

2 nm

2 pm

200 fm

What type of radiation has the wavelength given by question 8?

gamma ray

X-ray

infrared

radio wave

10.

A metal surface has a work function of 2.5 eV. What color light must hit it for electrons to be emitted?

red

green

dark blue

violet

11.

A 450 nm wavelength photon strikes the metal surface in question 10, what is the maximum energy of the emitted electrons?

0.26 eV

0.51 eV

2.76 eV

12.

What is the Compton wavelength?

2.1 nm

2.43 pm

2.45 fm

27 fm

13.

A 8300 eV photon compton scatters at 0 degrees. What is the wavelength of the scattered photon?

0.14 nm

0.15 nm

0.16 nm

0.17 nm

14.

A 0.15 nm photon scatters at 90 degrees. What is the wavelength of the scattered photon?

0.1476 nm

0.15 nm

0.1515 nm

0.1524 nm

15.

What is the energy of the scattered electron in question 14?

40 eV

63 eV

136 eV

16.

What is the wavelength associated with a 1 gm B-B traveling at 10 m/s?

2x10^-5 m

6.6x10^-5 m

2.8x10^-30 m

6.6x10^-32 m

17.

What is the wavelength of an electron traveling at 2x10⁶ m/s?

2x10^-5 m

3.6x10^-8 m

3.6x10^-10 m

2x10^-25 m

18.

What is the wavelength of a proton traveling at 2x10⁶ m/s?

2x10^-13 m

2x10^-14 m

2x10^-15 m

4.8 mm

19.

What is the wavelength of a photon with the same momentum (hf/c) as the the proton in the previous question?

2x10^-12 m

2x10^-13 m

2x10^-14 m

2x10^-15 m

20.

Who formulated the "Uncertainty Principle"?

Niels Bohr

Max Born

Werner Heisenberg

Wolfgang Pauli

Erwin Schrodinger

21.

If an electron is confined to a space the size of a nucleus (~1x10^-15 m), what is the uncertainty in its momentum?

1x10^-15 kg m/s

1x10^-17 kg m/s

1x10^-19 kg m/s

1x10^-21 kg m/s

22.

If the electron in question 5 has a momentum at least equal to the uncertainty in its momentum, what is its speed?

1x10⁵ m/s

1.9924x10⁸ m/s

2.99999x10⁸ m/s

1x10¹¹ m/s

23.

What is the energy of the electron in question 6? (This is used to prove that electrons can't exist in a nucleus.)

187.5 MeV

350 MeV

487.5 MeV

3.4 GeV

24.

Repeat the steps in 21, 22 and 23 above to estimate the energy of an electron confined to a space the size of an atom (~1x10^-10)?

1 eV

3.4 eV

100 eV

1 MeV

25.

If a certain quantum energy state exists for only 1 ns, what is the uncertainty in the energy?

1 eV

.05 eV

.0007 eV

6.25x10^-7 eV