Question

Calculate frequency of a photon having an energy of 2 electron volt.

• A. 4.8 × 1014s-1
• B. 4.8 × 1010s-1
• C. 2.0 × 1014s-1
• D. 3.5 × 10-7s-1

Answer 1

Answer: (A)

4.8 × 1014s-1

Answer 2

The energy ($E$) of a photon is related to its frequency ($\nu$) by Planck's equation: $E = h\nu$. To find the frequency, we rearrange the formula: $\nu = \frac{E}{h}$. Given energy $E = 2$ electron volts (eV). We convert this to Joules (J) using the conversion factor $1 \text{ eV} = 1.602 \times 10^{-19} \text{ J}$: $E = 2 \text{ eV} \times (1.602 \times 10^{-19} \text{ J/eV}) = 3.204 \times 10^{-19} \text{ J}$. Planck's constant $h \approx 6.626 \times 10^{-34} \text{ J.s}$. Now, we calculate the frequency: $\nu = \frac{3.204 \times 10^{-19} \text{ J}}{6.626 \times 10^{-34} \text{ J.s}} \approx 4.835 \times 10^{14} \text{ s}^{-1}$. This value is approximately $4.8 \times 10^{14} \text{ s}^{-1}$.