A point particle of charge q1=4.5*10^-6 is placed on the x-axis at x=-10 cm. A second particle of charge q2 is placed on the x-axis at x=+25 cm. The electric field at the origin is zero. Determine the charge q2

Ascientist notices that an oil slick floating on water when viewed from above has many different colors reflecting off the surface, making it look rainbow-like (an effect known as iridescence). she aims a spectrometer at a particular spot and measures the wavelength to be 750 nm (in air). the index of refraction of water is 1.3