Question

In the experiment on photoelectric effect, the graph between E_K (max) and ν is found to be a straight line as shown in figure-Calculate the threshold frequency–

• A. 3 × 10¹⁸ s^–1
• B. 6 × 10¹⁸ s^–1
• C. 6 × 10¹⁴ s^–1
• D. 2 Hz

Answer 1

Answer: (A)

3 × 10¹⁸ s^–1

Answer 2

K_max = hν – φ

φ is the intercept on y-axis

and h is the slope.

h = $\frac { 3.6 \times 10 ^ { - 15 } } { 4 \times 10 ^ { 18 } } =$9 × 10^–34 J-s

φ = 2 × 10^–15 J

hν₀ = 2 × 10^–15 J

ν₀ = 3.03 × 10¹⁸