As you move from left to right across the electromagnetic spectrum in the image, the wavelength becomes

The shortest wavelength is on the (high energy)left side of this diagram with Gamma rays. The longest wavelength waves are radio, around 3 meters. So, as you progress, the wavelengths get A) longer.

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.