Visible light encompasses wavelengths ranging from 400 nm to 780 nm . Determine the energy range of the photons of visible light.

Correct answer: D. 2.56 × 10^ -19 J to 5.00 × 10^ -19 J The energy of a photon is given by the formula E = (hc)/(λ) . For the lower limit of wavelength ( λ = 400 nm ): E_ = 6.626 × 10^ -34 × 3 × 10^8 400 × 10^ -9 E_ = 4.97 × 10^ -19 J 5.00 × 10^ -19 J For the upper limit of wavelength ( λ = 780 nm ): E_ = 6.626 × 10^ -34 × 3 × 10^8 780 × 10^ -9 E_ = 2.55 × 10^ -19 J 2.56 × 10^ -19 J Thus, the energy range of the photons of visible light is 2.56 × 10^ -19 J to 5.00 × 10^ -19 J .

Concepts Of Physics MCQ Edition [Volume 2]

Exam: Concepts Of Physics MCQ Edition [Volume 2]
Subject: Physics
Chapter: Photoelectric Effect and Wave–Particle Duality

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Photoelectric Effect and Wave–Particle Duality

Visible light encompasses wavelengths ranging from 400 nm to 780 nm...

Visible light encompasses wavelengths ranging from

400 \text{ nm}

780 \text{ nm}

. Determine the energy range of the photons of visible light.

Options

A $1.28 \times 10^{-19} \text{ J}$ to $2.50 \times 10^{-19} \text{ J}$
B $2.56 \times 10^{-17} \text{ J}$ to $5.00 \times 10^{-17} \text{ J}$
C $5.12 \times 10^{-19} \text{ J}$ to $10.0 \times 10^{-19} \text{ J}$
D $2.56 \times 10^{-19} \text{ J}$ to $5.00 \times 10^{-19} \text{ J}$

Correct answer

D. $2.56 \times 10^{-19} \text{ J}$ to $5.00 \times 10^{-19} \text{ J}$

Step-by-step solution

The energy of a photon is given by the formula

E = \dfrac{hc}{\lambda}

.

For the lower limit of wavelength (

\lambda = 400 \text{ nm}

E_{\text\max} = \dfrac{6.626 \times 10^{-34} \times 3 \times 10^8}{400 \times 10^{-9}}

E_{\text\max} = 4.97 \times 10^{-19} \text{ J} \approx 5.00 \times 10^{-19} \text{ J}

For the upper limit of wavelength (

\lambda = 780 \text{ nm}

E_{\text\min} = \dfrac{6.626 \times 10^{-34} \times 3 \times 10^8}{780 \times 10^{-9}}

E_{\text\min} = 2.55 \times 10^{-19} \text{ J} \approx 2.56 \times 10^{-19} \text{ J}

Thus, the energy range of the photons of visible light is

2.56 \times 10^{-19} \text{ J}

5.00 \times 10^{-19} \text{ J}

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