Which phrase best describes nuclear fusion?(1 point) a series of reactions in which particles from one reaction trigger the next reaction

the spontaneous emission of radiation from an unstable nucleus

the process by which a large nucleus is divided into smaller nuclei

the process by which small nuclei combine into a larger nucleus

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.