 University Physics Volume 3

# Chapter 6

6.1

Bunsen’s burner

6.2

The wavelength of the radiation maximum decreases with increasing temperature.

6.3

$Tα/Tβ=1/3≅0.58,Tα/Tβ=1/3≅0.58,$ so the star $ββ$ is hotter.

6.4

$3.3 × 10 −19 J 3.3 × 10 −19 J$

6.5

No, because then $ΔE/E≈10−21ΔE/E≈10−21$

6.6

$−0.91−0.91$ V; 1040 nm

6.7

$h = 6.40 × 10 −34 J · s = 4.0 × 10 −15 eV · s; − 3.5 % h = 6.40 × 10 −34 J · s = 4.0 × 10 −15 eV · s; − 3.5 %$

6.8

$(Δλ)min=0m(Δλ)min=0m$ at a $0°0°$ angle; $71.0pm+0.5λc=72.215pm71.0pm+0.5λc=72.215pm$

6.9

121.5 nm and 91.1 nm; no, these spectral bands are in the ultraviolet

6.10

$v2=1.1×106m/s≅0.0036c;v2=1.1×106m/s≅0.0036c;$ $L2=2ℏK2=3.4eVL2=2ℏK2=3.4eV$

6.11

29 pm

6.12

$λ = 2 π n a 0 = 2 ( 3.324 Å ) = 6.648 Å λ = 2 π n a 0 = 2 ( 3.324 Å ) = 6.648 Å$

6.13

$λ=2.14pm;λ=2.14pm;$ $K=261.56keVK=261.56keV$

6.14

$0.052 ° 0.052 °$

6.15

doubles it

### Conceptual Questions

1 .

yellow

3 .

goes from red to violet through the rainbow of colors

5 .

would not differ

7 .

human eye does not see IR radiation

9 .

No

11 .

from the slope

13 .

15 .

the particle character

17 .

19 .

no; yes

21 .

no

23 .

right angle

25 .

no

27 .

They are at ground state.

29 .

31 .

increase

33 .

for larger n

35 .

Yes, the excess of 13.6 eV will become kinetic energy of a free electron.

37 .

no

39 .

X-rays, best resolving power

41 .

proton

43 .

negligibly small de Broglie’s wavelengths

45 .

to avoid collisions with air molecules

47 .

49 .

51 .

yes

53 .

yes

### Problems

55 .

a. 0.81 eV; b. $2.1×1023;2.1×1023;$ c. 2 min 20 sec

57 .

a. 7245 K; b. 3.62 μm

59 .

61 .

$4.835×10184.835×1018$ Hz; 0.620 Å

63 .

263 nm; no

65 .

3.68 eV

67 .

4.09 eV

69 .

5.60 eV

71 .

a. 1.89 eV; b. 459 THz; c. 1.21 V

73 .

264 nm; UV

75 .

$1.95 × 10 6 m/s 1.95 × 10 6 m/s$

77 .

$1.66 × 10 − 32 kg · m/s 1.66 × 10 − 32 kg · m/s$

79 .

56.21 eV

81 .

$6.63×10−23kg·m/s;6.63×10−23kg·m/s;$ 124 keV

83 .

82.9 fm; 15 MeV

85 .

(Proof)

87 .

$Δ λ 30 / Δ λ 45 = 45.74 % Δ λ 30 / Δ λ 45 = 45.74 %$

89 .

121.5 nm

91 .

a. 0.661 eV; b. –10.2 eV; c. 1.511 eV

93 .

3038 THz

95 .

97.33 nm

97 .

a. h/$π;π;$ b. 3.4 eV; c. – 6.8 eV; d. – 3.4 eV

99 .

$n = 4 n = 4$

101 .

365 nm; UV

103 .

no

105 .

7

107 .

145.5 pm

109 .

20 fm; 9 fm

111 .

a. 2.103 eV; b. 0.846 nm

113 .

80.9 pm

115 .

$2.21 × 10 − 19 m/s 2.21 × 10 − 19 m/s$

117 .

$9.929 × 10 32 9.929 × 10 32$

119 .

$γ=1060;γ=1060;$ 0.00124 fm

121 .

24.11 V

123 .

a. $P=2I/c=8.67×10−6N/m2;P=2I/c=8.67×10−6N/m2;$ b. $a=PA/m=8.67×10-4m/s2;a=PA/m=8.67×10-4m/s2;$ c. 74.91 m/s

125 .

$x = 4.965 x = 4.965$

127 .

$7.124 × 10 16 W/m 3 7.124 × 10 16 W/m 3$

129 .

1.034 eV

131 .

$5.93 × 10 18 5.93 × 10 18$

133 .

387.8 nm

135 .

a. $4.02×1015;4.02×1015;$ b. 0.533 mW

137 .

a. $4.02×1015;4.02×1015;$ b. 0.533 mW; c. 0.644 mA; d. 2.57 ns

139 .

a. 0.132 pm; b. 9.39 MeV; c. 0.047 MeV

141 .

a. 2 kJ; b. $1.33×10−5kg·m/s;1.33×10−5kg·m/s;$ c. $1.33×10−5N;1.33×10−5N;$ d. yes

143 .

a. 0.003 nm; b. $105.56°105.56°$

145 .

$n = 3 n = 3$

147 .

a. $a0/2;a0/2;$ b. $−54.4eV/n2;−54.4eV/n2;$ c. $a0/3,−122.4eV/n2a0/3,−122.4eV/n2$

149 .

a. 36; b. 18.2 nm; c. UV

151 .

396 nm; 5.23 neV

153 .

7.3 keV

155 .

728 m/s; $1.5μV1.5μV$

157 .

$λ = h c / K ( 2 E 0 + K ) = 3.705 × 10 − 12 m, K = 100 keV λ = h c / K ( 2 E 0 + K ) = 3.705 × 10 − 12 m, K = 100 keV$

159 .

$Δ λ c ( electron ) / Δ λ c ( proton ) = m p / m e = 1836 Δ λ c ( electron ) / Δ λ c ( proton ) = m p / m e = 1836$

161 .

(Proof)

163 .

$5.1 × 10 17 Hz 5.1 × 10 17 Hz$

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