Temperature of The Earth

Score: 4 Points

What would be the mean temperature on the Earth’s surface if we ignore the greenhouse effect, assume that the Earth is a perfect black body whose orbit around the Sun is circular and take into account its non-vanishing albedo?
Given that,
Average Earth-Sun distance = 149.6 million km
Radius of the Sun = 695,510 km
Effective temperature of the Sun = 5800k

Answer using three significant digits.

The albedo, $a$ = $0.39$. Your answer should be in SI unit.

To know more about the temperature range for the Habitable zone.

Source: IOAA 2013