Answer:
Option B. 4.74×10¯¹⁹ J.
Explanation:
The following data were obtained from the question:
Wavelength (λ) = 4.2×10¯⁷ m
Energy (E) =.?
Next, we shall determine the frequency of the wave. This can be obtained as follow:
Wavelength (λ) = 4.2×10¯⁷ m
Velocity (v) = constant = 3×10⁸ m/s
Frequency (f) =.?
v = λf
3×10⁸ = 4.2×10¯⁷ × f
Divide both side by 4.2×10¯⁷
f = 3×10⁸ / 4.2×10¯⁷
f = 7.143×10¹⁴ s¯¹
Therefore, the frequency of the wave is 7.143×10¹⁴ s¯¹.
Finally, we shall determine the energy of the wave using the following formula
E = hf
Where
E is the energy.
h is the Planck's constant
f is the frequency
Thus, the enery of the wave can be obtained as follow:
Frequency (f) = 7.143×10¹⁴ s¯¹.
Planck's constant = 6.63×10¯³⁴ Js
Energy (E) =..?
E = hf
E = 6.63×10¯³⁴ × 7.14×10¹⁴
E = 4.74×10¯¹⁹ J
Therefore, the energy of the wave is 4.74×10¯¹⁹ J.
