Two monochromatic lamps, A and B

PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation

Problem

Two monochromatic lamps, A and B, emit light of frequencies

5.0\times10^{14}\,\text{Hz}

and

8.0\times10^{14}\,\text{Hz}

respectively. Lamp A has an output power of

10\,\text{mW}

whereas lamp B has an output power of

6\,\text{mW}

. The beams from the two lamps are made to fall normally and simultaneously on identical photosensitive plates of area

1.0\,\text{cm}^2

, each having a quantum efficiency of

60\%

for the respective wavelengths. (i) For each lamp acting alone, calculate the saturation current obtained from its plate. (ii) When both lamps illuminate the same plate together, determine the resultant saturation current and justify your method of calculation. (iii) Comment, with reason, on whether the difference in photon energies of the two lamps influences the saturation current produced."

Related theory

Einstein's Photoelectric Equation
Quantum Explanation of PE
Photoelectric effect
Dual Nature of Radiation and Matter
The photoelectric effect

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