Final answer:
Option (D), The energy of a single photon with a frequency of 7.81 x 10⁻¹³ Hz is calculated using the formula E = hf. Using Planck’s constant (6.626 × 10⁻³⁴ J·s), the energy is found to be 5.17 x 10⁻²⁰ J.
Step-by-step explanation:
To calculate the energy of a single photon with a given frequency, we can use the formula E = hf, where E is the energy of the photon in joules, h is Planck’s constant (6.626 × 10⁻³⁴ J·s), and f is the frequency of the photon in hertz (Hz). In the case of a photon with a frequency of 7.81 x 10⁻¹³ Hz, the energy can be calculated as follows:
E = (6.626 × 10⁻³⁴ J·s) × (7.81 x 10⁻¹³ Hz)
E = 6.626 × 7.81 x 10⁻¹³ × 10⁻³⁴
E = 5.17 x 10⁻²⁰ J
Therefore, the correct answer is (d) 5.17 x 10⁻²⁰ J.