Explain what it's meant by refraction of light

Macy always thought there were only a few hair colors blonde brown and black however when she actually began looking around she saw varying shades of these hair color what is a possible reason for so many different hair colors

An electromagnetic wave with frequency 65.0 hz travels in aninsulating magnetic material that has dielectric constant 3.64 andrelative permeability 5.18 at this frequency. the electric fieldhas amplitude 7.20 \times 10^{ - 3} {\rm v}/{\rm m}. a. what is the speed of propagation of the wave? b. what is the wavelength of the wave? c. what is the amplitude of the magnetic field? d. what is the intensity of the wave?

An object with a mass of 1.5 kg changes its velocity from + 15 m/s to +22 m/s during a time interval of 3.5 seconds. what impulse was delivered to the objects?