The beam angle of a lamp is the angle at which light is emitted. So a small angle of 20 degrees would be appropriate for a spot light, focusing light on just one small area. If you want more general lighting, spreading light over a whole room, a larger angle of perhaps 80 degrees would be preferred.However, the amount of light that falls in a particular space will fall In most domestic lighting situations beam angles of 30-45 degrees are sufficient to light a room comfortably. Within limits it doesn’t make much difference if the beam angles are slightly different – for example you would be unlikely to notice the difference between 35 and 38 degrees.
In the past, LEDs which were designed for focused light in a narrow area. Now with the great advantages of LED lights,mostly because of the long service life and energy efficiency, LED light are designed with a wide range of beam angles, from narrow spotlights to wider general lighting. LEDs can be bought in a range of beam angles from 15, 30, 40, 45, 60, 90, to 120 degrees,even to 360degrees . On the other hand, it means that there is a lot of choice on the market. More choice may cause more confusion.
When you choose a LED light you should always remember the important rule: which area the LED light is gonna applied for.Make sure the LED light you install is to work out exactly what is needed for each area. A room lit by a single ceiling light will definitely need the widest beam angle available, whereas a room with several down lights placed in various areas of the room can use the average 35-40 beam angle as the lights will cover different areas of the room and overlap with each other. You will need a different type of LED light bulb for a table lamp than for a ceiling light, otherwise you might find that you are throwing light directly back at the ceiling instead of lighting up your desk !