Our understanding of the atom has changed over time. which idea that was once accepted is now considered scientifically inaccurate?
a. the nucleus is the center of the atom.
b. an atom is solid material.
c. electrons have a negative charge.
d. electrons are arranged in layers.

Asquare 1m x 1m plate is shown below. all four of its edges are kept at 0 co. at t=0the temperature distribution is given by: y xtsins n75)=.a) using separation of variables determine the temperature distribution t(x,y,t)along the plate at any time t.b) discretize the heat conduction equation +=22222 txtusing a second-order centered difference scheme for the two second derivatives and a first-order forward euler scheme for the first derivative. using von neumann stability analysis, determine the stability criterion for the proposed discretization scheme in terms of , hand t. solve for the maximum allowable time step tmax