Question

Figure represents a graph of kinetic energy of most energetic photoelectrons (in eV) and frequency metal used as cathode in photoelectric experiment. The threshold frequency of light for the photoelectric emission from the metal is :

• A. $1 \times 10 ^ { 14 } \mathrm {~Hz}$
• B. $1.5 \times 10 ^ { 14 } \mathrm {~Hz}$
• C. $2 \times 10 ^ { 14 } \mathrm {~Hz}$
• D. $2.7 \times 10 ^ { 14 } \mathrm {~Hz}$

Answer 1

Answer: (D)

$2.7 \times 10 ^ { 14 } \mathrm {~Hz}$

Answer 2

; From graph

According to Einstein’s photoelectric equation

$K _ { \max } = h v - h v _ { 0 }$

Or

Or