The wavelengths of light emitted by a firefly span the visible spectrum but have maximum intensity near 550 nm. a typical flash lasts for 100 ms and has a power of 1.2 mw. if we assume that all of the light is emitted at the peak-intensity wavelength of 550 nm, how many photons are emitted in one flash?

Explanation:

First of all, let's calculate the energy of a single photon of wavelength

which is given by

The power of the flash is

and the time it lasts is

so the total energy delivered in one flash is

This energy contains exactly N photons each of energy , so the number of photons emitted in one flash is

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.

there are no components of a physical goal mentioned on the list of choices that you've provided.