The left pic is definitely heat or light burn. The right pic could be nute burn or heat burn; most likely heat considering the other picture. Was the plant close to the light? What kind of light was it? Are the burned tips near the bottom of the plant or top? With nute burn, it almost always starts on the tips of the lowest set of leaves and works its way up as the plant drinks the water up it's stem. Heat burn is always worst on top of the plant closest to the light.