NCERT Class XII Chapter
Dual Nature of Radiation and Matter
Questions With Solutions
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Question : 8
Total: 37
The threshold frequency for a certain metal is 3.3 × 10 14 Hz. If light of frequency 8.2 × 10 14 Hz is incident on the metal, predict the cut off voltage for the photoelectric emission.
Solution:
According to Einstein’s relation, hu = h u 0 +
m v max 2
Maximum kinetic energy of emitted electron,
m v max 2 = h (v - v 0 )
= 6.63 ×10 − 34 (8.2 × 10 14 - 3.3 × 10 14 )
= 32.49 ×10 − 20 Jouke = 2 eV
∴ Cut off potential for emitted electron will be 2 volt.
Maximum kinetic energy of emitted electron,
= 6.63 ×
= 32.49 ×
∴ Cut off potential for emitted electron will be 2 volt.
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