Statement 1: It is observed that sometimes an incandescent bulb glows brighter and sometimes it glows dim.
Statement 2: Glowing brighter and dimmer depends on heating effect of current. More current produces more heating effect making the bulb glow brighter and vice-versa.
Both the statements are true but statement 2 is not the correct explanation of statement 1.
Both the statements are true and statement 2 is the correct explanation of statement 1.