Question

Problem # 1

How many photons do you absorb per second when standing at the beach? The sun delivers

500W/m^2 at 560nm. The sun shines on 0.9m^2 of your skin. Assume all photons are absorbed.

(5 marks)

Problem # 2

Monochromatic light (that is, light of a single wavelength) is to be absorbed by a sheet of photographic film

and thus recorded on the film. Photon absorption will occur if the photon energy equals or exceeds 0.6 eV,

the smallest amount of energy needed to dissociate an AgBr molecule in the film.

(a) What is the greatest wavelength of light that can be recorded by the film? (5 marks)

(b) In what region of the electromagnetic spectrum is this wavelength located? (5 marks)

Problem # 3

Suppose the fractional efficiency of a cesium surface (with work function 1.80 eV) is 1.0* 10^16; that is, on

average one electron is ejected for every 10^16 photons that reach the surface. What would be the current

of electrons ejected from such a surface if it were illuminated with 600 nm light from a 2.00 mW laser and

all the ejected electrons took part in the charge flow? (5 marks)

Problem # 4

In a photoelectric experiment using a sodium surface, you find a stopping potential of 1.85 V for a

wavelength of 300 nm and a stopping potential of 0.820 V for a wavelength of 400 nm.

From these data find

(a) a value for the Planck constant, (5 marks)

(b) the work function & for sodium, (5 marks)

and (c) the cutoff wavelength for sodium.(5 marks)​

Answer 1

how did you assume that anyone can answer many questions for 15 points.