Alaboratory uses a laser with a light wavelength of 910nm. if the lab turns the laser on for 20 picoseconds, how many wavelengths can be found in the resulting wave pulse?

6593.4

Explanation:

wavelength, λ = 910 nm = 910 x 10^-9 m

Speed of laser = 3 x 10^8 m/s

t = 20 pico seconds

Distance traveled by laser in this time, d = c x t

d = 3 x 10^8 x 20 x 10^-12 = 6 x 10^-3 m

number of wavelengths, n = d / λ

n = (6 x 10^-3) / (910 x 10^-9)

n = 6593.4

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.