- #1

Hannah Vioula

- 2

- 0

## Homework Statement

i)A beam of light at wavelength 600nm, with spectral width of 4nm and spectral radiance of 1300 Wm

^{-2}μm

_{-1}, illuminates an area of 10cm

^{2}. What is the voltage this beam could generate if converted to energy?

ii) What current could this beam produce?

iii) How would the current change if the width of the beam were 5 meV?

## Homework Equations

i) Voltage = hf / charge = change in energy / charge = h*c / q*λ

ii)

Spectral Radiance= e

_{λ}= hf φ

_{λ}

Where, Spectral Flux Density = φ

_{λ}

f=c/λ

Current Density = q * φ

_{λ}* δλ = I / A

iii) Absolutely no idea what to use.

Maybe, E (in eV)=1.24 / λ (in μm)

## The Attempt at a Solution

[/B]

i)

I need max voltage available, so I ignore spectral width.

Voltage = h*c/ (600*10

^{-9}* q)= 2.060 Volts

ii)

I get flux density first

Spectral radiance= e

_{λ}

Spectral flux density = φ

_{λ}

Rearranging equation -- -- > Spectral Radiance= e

_{λ}= hf φ

_{λ}

φ

_{λ}= e

_{λ}* λ / h*c = 1300 * (600*10

^{-9}) / h*c = 4.58*10

^{21}

Rearranging equation, Current Density = q * φ

_{λ}* δλ = I / A

I = q * φ

_{λ}* δλ * A = 3.68 mA

iii) Not a the faintest of idea of what to do here...

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