what is the light that appears when you touch something metal while you have alot of static electricity

An object weigh 40n in air ,weigh 20n when submerged in water,and 30n when submerged in a liquid of unknown liquid density.what is the density of unknown of liquid?

Need this now! do pilots live long

Suppose a diode consists of a cylindrical cathode with a radius of 6.200×10^−2 cm , mounted coaxially within a cylindrical anode with a radius of 0.5580 cm . the potential difference between the anode and cathode is 260 v . an electron leaves the surface of the cathode with zero initial speed (v initial=0). find its speed vfinal when it strikes the anode.