Chapter 12, Problem 12.140MP

Interpretation Introduction

(a)

Interpretation:

The number of photons per second emitted by laser is to be calculated.

Concept introduction:

The light can have dual nature particles as well as wave nature. The wave nature of light is best described by its frequency, wavelength, and amplitude. The expression of energy of light and wavelength $\left(\text{λ}\right)$ is as follows:

$E_g=\frac{hc}{\text{λ}}$

Where,

• $E_g$ is band gap of diode.
• $h$ is known as Plank’s constant and its value is $\text{6}\text{.626}\times {\text{10}}^{-\text{34}}\text{ J}\cdot \text{s}$
• $c$ is speed of light and its value is $3.0\times {10}^8\text{ m/s}$.
• $\text{λ}$ is wavelength of light.

Interpretation Introduction

(b)

Interpretation:

The amount of current that is flowed in circuit after absorption of all photons by solar cells is to be calculated.

Concept introduction:

The light can have dual nature particles as well as wave nature. The wave nature of light is best described by its frequency, wavelength, and amplitude.

The expression of energy of light and wavelength $\left(\text{λ}\right)$ is as follows:

$E_g=\frac{hc}{\text{λ}}$

Where,

• $E_g$ is band gap of diode.
• $h$ is known as Plank’s constant and its value is $\text{6}\text{.626}\times {\text{10}}^{-\text{34}}\text{ J}\cdot \text{s}$
• $c$ is speed of light and its value is $3.0\times {10}^8\text{ m/s}$.
• $\text{λ}$ is wavelength of light.

The expression to calculate current flows through circuit is as follows:

The expression to calculate current from number of electrons is as follows:

$I=\frac{Q}{t}$

Where,

• $I$ is current flow through circuit.
• $Q$ is total charge flows

Or,

$I=\frac{\left(\text{Total number of electrons}\right)\left(\text{charge per electron}\right)}{\left(\text{Time}\right)}$