Answer:
a. 4100 K before the eruption and 9000 K after the eruption
Step-by-step explanation:
As color changes from red or orange to blue in seven color of rainbow , temperature increases . Since before eruption , color was orange which turns to bluish so temperature will be increased after eruption.
At 10000 K a hot object starts emanating blue color , which becomes invisible ultraviolet at temperature beyond 10000. Hence temperature of 36000 K or 37000 K is ruled out . The correct option is , therefore a ).