Dual Nature of Radiation MCQ with Answers

Dual Nature of Radiation MCQ with Answers

56) If threshold wavelength for tungsten is 2300?A⁰, then energy of the electrons emitted by UV light of wavelength 1800?A⁰?is

Answer is:

2.4??10^?12?erg

Explanation:

use W=hV_o and E = hc/(/lambda)

57) If maximum velocity with which an electron can be emitted from a photo cell is 3.75?10⁸cms^?1, then stopping potential is

Answer is:

40 volts

Explanation:

Use 1/2mv²_max=hv??_? and W=hV_o

58) Wavelength of light incident on a photo cell is 3000?A⁰, if stopping potential is 2.5 volts, then work function of the cathode of photo cell is

Answer is:

1.64 eV

Explanation:

use W=hV_o and E = hc/(/lambda)

59) If the frequency of incident light on a certain metal is 8.2??10¹⁴Hz having threshold frequency of 3.3??10¹⁴?Hz , then cut off potential is

Answer is:

3 V

Explanation:

use W=hV_o and E = hc/(/lambda) and threshold frequency=c/(/ambda)

60) If light of frequency?10¹⁵?Hz is incident on sodium having work function 2.5eV,then energy of emitted photoelectrons is

Answer is:

2.6??10^?19?J

Explanation:

use W=hV_o and E = hc/(/lambda)

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