Assertion (A): In the visible spectrum of light, red light is more energetic than green light. Reason (R): The wavelength of red light is more than that of green light.

The correct answer is D because Assertion A is false while Reason R is true. In the electromagnetic spectrum, the energy of light is inversely proportional to its wavelength. This relationship is defined by the formula where energy equals Planck's constant times the speed of light divided by the wavelength. Red light has the longest wavelength in the visible spectrum, which means it has the lowest frequency and the lowest energy. Green light has a shorter wavelength than red light, making it more energetic. Therefore, the assertion that red light is more energetic than green light is incorrect. The reason is true because red light indeed has a longer wavelength, approximately 620 to 750 nanometers, compared to green light, which ranges from approximately 495 to 570 nanometers. Since A is false and R is true, option D is the correct choice.