Multiple-Choice Questions

1) Which of these is not a form of electromagnetic radiation?

A) DC current from your car battery

B) light from your camp fire

C) x-rays in the doctor's office

D) ultraviolet causing a suntan

E) television signals

Page Ref: 2.1

2) A wave's velocity is the product of the

A) frequency times the period of the wave.

B) period times the energy of the wave.

C) amplitude times the frequency of the wave.

D) frequency times the wavelength of the wave.

E) amplitude times the wavelength of the wave.

Page Ref: 2.1

4) If a wave's frequency doubles, its wavelength 

A) is halved.

B) is also doubled.

C) is unchanged, as c is constant.

D) is now 4× longer.

E) becomes 16× longer.

Page Ref: 2.1

5) The speed of light in a vacuum is

A) 300,000 km/sec.

B) 768 km/hour.

C) 186,000 miles per hour.

D) h = E/c.

E) not given.

Page Ref: 2.2

6) Which of these is constant for all forms of E-M radiation in a vacuum?

A) amplitude

B) wavelength

C) frequency

D) velocity

E) photon energy

Page Ref: 2.3

7) The two forms of E-M radiation that experience the least atmospheric opacity are

A) light and radio waves.

B) light and infrared waves.

C) microwaves and television waves.

D) X and gamma radiation.

E) ultraviolet and infrared waves.

Page Ref: 2.3

8) The radiation our eyes are most sensitive to lies in the color

A) red at 6563 Angstroms.

B) yellow-green at about 550 nm.

C) violet at 7,000 Angstroms.

D) blue at 4,321 nanometers.

E) black at 227 nm.

Page Ref: 2.3

9) Medium A blocks more of a certain wavelength of radiation than medium B.  Medium A has a higher

A) transparency.

B) seeing.

C) clarity.

D) opacity.

E) albedo.

Page Ref: 2.3

10) In the Kelvin scale, absolute zero lies at

A) zero K.

B) 273 degrees C

C) -373 degrees C.

D) Both A and B are correct.

E) Both A and C are correct.

Page Ref: 2.4

11) What is true of a blackbody?

A) It appears black to us, regardless of its temperature.

B) Its energy is not a continuum.

C) Its energy peaks at the wavelength determined by its temperature.

D) If its temperature doubled, the peak in its curve would be doubled in wavelength.

E) It has a complete absence of thermal energy.

Page Ref: 2.4

12) The temperature scale that places zero at the point where all atomic and molecular motion ceases is

A) Fahrenheit.

B) Celsius.

C) Kelvin.

D) centigrade.

E) Ransom.

Page Ref: 2.4

13) The total energy radiated by a blackbody depends on

A) the fourth power of its temperature.

B) the square of its temperature.

C) the square root of its temperature.

D) the cube root of its temperature.

E) the cube of its temperature.

Page Ref: 2.4

14) Doubling the temperature of a blackbody will increase its energy by

A) 1.5× more

B) 2.5× more

C) 4× more

D) 5× more

E) 16× more

Page Ref: 2.4

15) If a star was the same size as our Sun, but was 81× more luminous, it must be

A) twice as hot as our Sun.

B) three times hotter than the Sun.

C) four times hotter than the Sun.

D) nine times hotter than the Sun.

E) 81 times hotter than the Sun.

Page Ref: 2.4

16) The Sun's observed spectrum is

A) a continuum with no lines, as shown by the rainbow.

B) a continuum with emission lines.

C) only absorption lines on a black background.

D) a continuum with absorption lines.

E) only emission lines on a black background.

Page Ref: 2.5

17) The element first found in the Sun's spectrum, then on Earth 30 years later, is

A) hydrogen.

B) helium

C) solarium.

D) technicum.

E) aluminum.

Page Ref: 2.5

18) A jar filled with gas is placed directly in front of  a second jar filled with gas.  Using a spectroscope to look at one jar through the other you observe dark spectral lines.  The jar closest to you contains

A) the hotter gas.

B) the cooler gas.

C) gas  at the same temperature as the other jar.

D) the exact same gas as the other jar.

E) gas at very high pressure.

Page Ref: 2.5

19) Which of these is emitted when an electron falls from a higher to lower orbital?

A) another electron

B) a positron

C) a neutrino

D) a photon

E) a graviton

Page Ref: 2.6

20) In Bohr's model of the atom, electrons

A) only make transitions between orbitals of specific energies.

B) are not confined to specific orbits.

C) are spread uniformly through a large, positive mass..

D) can be halfway between orbits.

E) move from orbit to orbit in many small steps.

Page Ref: 2.6

21) In general, the spectral lines of molecules are

A) more complex than those of atoms.

B) the same as the atoms they contain.

C) only absorption lines.

D) less complex than those of atoms.

E) nonexistent.

Page Ref: 2.6

22) Electromagnetic radiation

A) can only travel in a dense medium.

B) has only the properties of waves.

C) can behave both as a wave and a packet of energy (photon).

D) is the same as a sound wave.

E) has nothing in common with radio waves.

Page Ref: 2.6

23) In a hydrogen atom, a transition from the 2nd to the 1st excited state will produce

A) the bright red Balmer alpha emission line..

B) no emission line.

C) a dark absorption line.

D) an ultraviolet spectral line.

E) three different emission lines.

Page Ref: 2.6

24) For hydrogen, the transition from the first to third excited state produces

A) a red emission line.

B) a blue green absorption line.

C) a violet emission line.

D) an infrared line.

E) an ultraviolet line.

Page Ref: 2.6

25) The observed spectral lines of a star are all shifted towards the red end of the spectrum.  

Which statement is true?

A) This is an example of the photoelectric effect.

B) This is an example of the Doppler effect.

C) The second law of Kirchhoff explains this.

D) The star is not rotating.

E) The star has a radial velocity towards us.

Page Ref: 2.7

26) If a source of light is approaching us at 3,000 km/sec, then all its waves are

A) blue shifted by 1%.

B) red shifted by 1%.

C) not affected, as c is constant regardless of the direction of motion.

D) blue shifted out of the visible spectrum into the ultraviolet.

E) red shifted out of the visible into the infrared.

Page Ref: 2.7

27) If the rest wavelength of a certain line is 600 nm., but we observe it at 594 nm, then

A) the source is approaching us at 1 % of the speed of light.

B) the source is approaching us at 0.1 % of the speed of light.

C) the source is receding from us at 10% of the speed of light.

D) the source is getting 1% hotter as we watch.

E) the source is spinning very rapidly, at 1% of the speed of light.

Page Ref: 2.7

28) According to the Zeeman effect, the splitting of a sunspot's  spectral lines is due to

A) their rapid rotation.

B) temperature variations.

C) their magnetic fields.

D) their radial velocity.

E) a Doppler shift,

Page Ref: 2.8