Assertion: The Nitrogen atom loses its 3 valence electrons to form its ion Reason: Nitrogen ion is an anion

(a) Both assertion (A) and Reason (R) are true, and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and Reason (R) are true, but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true, but reason (R) is false.
(d) Assertion (A) is false, but reason (R) is true

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.