4. From  the  equation in the Lecture 5 notes for D_L   at low redshifts  (D_L  =cz/Ho (1 + z/2(1-qo))  it is clear that for reasonable values of q₀ (i.e. less than unity) D_L is always larger than cz/H₀, and hence the apparent magnitude will be fainter than the naive estimate. This is primarily arising from the redshift reducing the bolometric flux. (See explanation of the two (1+z) factors leading up to equation 6 in the Lecture 5 notes.)