The beam angle affects how much light arrives at the illuminated area.
Many spotlights emit light at a certain angle due to its design. This is called the beam angle. The angle of radiation determines the size of the light cone, as well as how much light actually arrives at the surface.
Light decreases in brightness over distance. The bundling of the light can ensure that enough light still comes to the illuminated object, even after a greater distance.
The larger the beam angle, the larger the light cone and so the faster the light becomes weaker.
A good demonstration of this is through a torch. When a torch is at a large angle and shines onto a wall, you will see a large beam of light. However, the brightness within the light cone on the wall is lower. After you set the zoom to a narrower angle, the light cone is reduced a lot, but the light at the targeted point is significantly brighter.
Lets understand the beam angle better. A beam angle of 120° is suitable for the general lighting of rooms. For example, if you want to highlight some art on the wall, you should choose a smaller beam angle. An angle of 90° is recommended to illuminate the hallway. These guidelines will help you illuminate effectively.