A nickel atom has an atomic number of 28 and an atomic mass of 59. What is the structure of this atom?
A. It has a central nucleus composed of 28 protons and 31 neutrons,
surrounded by an electron cloud containing 28 electrons.
B. It has a central nucleus composed of 28 protons and 28 neutrons,
surrounded by an electron cloud containing 31 electrons.
C. It has a central nucleus composed of 31 protons and 28 neutrons,
surrounded by an electron cloud containing 28 electrons.
D. It has a central nucleus composed of 28 protons and 59 neutrons,
surrounded by an electron cloud containing 28 electrons.

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90

If element x has 99 protons how many electrons does it have