Question

of the apparent visual magnitudes listed below, which corresponds to the faintest star in our sky that can still be seen with the naked eye?
-4.5
+2.5
+6.7
0.2
-2.3

Explanation:

Step1: Recall magnitude scale

Apparent visual magnitude: lower (more positive) numbers mean fainter; negative/less positive mean brighter. Naked eye limit ~+6.5 to +7.

Step2: Compare magnitudes

Check options: -4.5 (very bright), +2.5 (bright), +6.7 (faint, near naked eye limit), 0.2 (bright), -2.3 (very bright). +6.7 is the most positive (faintest) among them, within naked eye range.

Answer:

+6.7