My friend and I were arguing over sun light. i said that since light take eight minutes to reach us on earth from sun, then if the sun should go dark we will still see light after eight minutes it died. But my friend said no. that sun is emitting radiation, once cut off nothing will radiate to earth meaning we will stop seeing sun light that very second. physicts in the house help us solve this

Your submission is correct and your friend's wrong. Einstein's Special theory of relativity clarifies the issue--the speed of light is the same for all observer i.e 3*10^8 m/s. This means there's a speed limit, it's not instantaneous!

Light travels roughly 300000km per second. But there is 151 million in between Earth and Sun, hence when we divide 151 million by 300000, we get 503.33 seconds light takes to go from Sun to Earth. Convert seconds to minutes gives ~8 minutes. Perhaps this would help your friend �

Highlighted is for TL;DR

You're correct, when distant stars go supernova and we report it because we just saw the light.
But the supernova occured billions of years ago. But the sheer distance of the star from us (light years). Means that we are just receiving the light now.

So if the sun suddenly went dark, it would take 8 minutes for us to see the lights go down.
Because light has a speed!