Which of the following is correct when the intensity of the light source is increased?
Choose one answer.
a. The number of photons emitted by the light source in unit time increases.
b. The total energy of the photons emitted per unit time decreases.
c. Photons are emitted with more energy.
d. Photons are emitted with more speed.
more photons in, more photons out
The correct answer is option A: The number of photons emitted by the light source in unit time increases.
When the intensity of a light source is increased, it means that the overall brightness or power of the light is increased. The intensity of light is directly proportional to the number of photons emitted by the light source in a given unit of time.
To understand why this is the correct answer, it's important to know that light is not a continuous stream, but is composed of discrete particles called photons. The energy and speed of individual photons do not change with the increase in intensity of the light source.
To visualize this, think of a light bulb. When you increase the power or intensity of the light bulb, it emits more photons per unit time. Each photon carries the same energy and travels at the same speed as before, but there are simply more photons being emitted.
Therefore, option A is correct: The number of photons emitted by the light source in unit time increases when the intensity of the light source is increased.