Acertain type of laser emits light that has a frequency of 7.2 × 1014 hz. the light, however, occurs as a series of short pulses, each lasting for a time of 3.7 × 10-11 s. (a) how many wavelengths are there in one pulse? (b) the light enters a pool of water. the frequency of the light remains the same, but the speed of the light slows down to 2.3 x 108 m/s. how many wavelengths are there now in one pulse?

a) 26 640

b) 26 640

Explanation:

Hello!

a)

We need first to know the wavelength of the laser, and this can be known from the relation between wavelength frequency and the velocity of ligth        c = fλ:

λ = c/f = (3x10^8 m/s) / (7.2 x 10^14 Hz) = 4.166 x 10^-7 m = 416.6 nm

Now, we need to know the spatial length of the pulse, and we are going to calculate it as follows:

d = c t = (3x10^8 m/s) (3.7 x 10^-11 s)  =1.11 x 10^-2 m

To know how many wavelengths are in one pulse its enough to divide these two quantityes:

d/λ =(ct)/(c/f) = ft = (7.2 x 10^14 Hz) (3.7 x 10^11 s) = 26 640

b)

From the previous result we said that the number of wavelengths in one pulse is just the division of d/λ which is the same as t*f, which in turn is independent of the velocity of light, therefore, the number of wavelengths in one pulse remains the same

they are playing too much beyblade in the office

explanation:

we're given that v₀ = 0 and a = 5.4 m/s². therefore, since v = at + v₀ for constant acceleration the equation for velocity is

after 28s,

m/s

which i would round to 150 m/s as my final answer