A.n2

B.n

C.1/n

D.1/n2

正确答案：n2

4、In hydrogen atom the angular momentum of the electron in the lowest energy state（）

A.2h

B.2p/h

C.h/2p

D.h/p

正确答案：h/2p

5、The ratio of the speed of the electron in the ground state of hydrogen atom to the speed of light is（）

A.2/137

B.1/237

C.1/2

D.1/137

正确答案：1/137

6、If the electron in hydrogen atom jumps from the third orbit to second orbit， the wavelength of th emitted radiation is given by（）

A.36/5R

B.5/R

C.5R/36

D.R/6

正确答案：36/5R

7、A proton and an electron， both at rest initially， combine to form a hydrogen atom in the ground state.A single photon is emit- ted in this process.What is its wavelength？（）

A.91.2 nm

B.15 mm

C.49 fm

D.357 nm

正确答案：91.2 nm

8、A beam of electrons bombards a sample of hydrogen.Through what potential difference must the electrons have been accelerated if the first line of the Balmer series is to be emitted？（）

A.569.3 V

B.35.7 V

C.0.6 V

D.12.1 V

正确答案：12.1 V

9、The longest wavelength in the Lyman series is 121.5 nm and the shortest wavelength in the Balmer series is 364.6 nm.Find the longest wavelength of light that could ionize hydrogen.（）

A.49.4 fm

B.91.13 nm

C.74.5 mm

D.8.3 nm

正确答案：91.13 nm

10、What is the shortest wavelength present in the Brackett series of spectral lines？（）

A.569.34 nm

B.327.89 nm

C.1.46 mm

D.91.13 nm

正确答案：1.46 mm

第四章单元测试

1、The energy quanta of an atomic oscillator that emits and absorbs orange light whose frequency is 5.00 ×1014 Hz is.（）.

A.7.13 eV

B.12.89 eV

C.3.89×10-19 J

D.2.08 eV

正确答案：2.08 eV

2、Ultraviolet light of wavelength 350 nm and intensity 1.00 W/m2 is directed at a potassium surface.The maximum kinetic energy of the photoelectrons is（）

A.17.6 eV

B.4.42×10-19 J

C.3.5 eV

D.6.9 eV

正确答案：3.5 eV

3、A metal surface illuminated by 8.5×1014 Hz light emits electrons whose maximum energy is 0.52 eV.The same surface illuminated by 12.0×1014 Hz light emits electrons whose maximum energy is 1.97 eV.The work function of the metal is（B ）。

A.3.0 eV

B.12.4 eV

C.47.5 eV

D.7.2 eV

正确答案：3.0 eV

4、The de Broglie wavelengths of a 46 g golf ball with a velocity of 30 m/s is（）