Layers of  the Sun:

Tbe Sun's body  is made up of several  layem Tbe  layer that forms  the viable surface of the Sun is called the photosphere-it  is  the surface that demarcates  Lady oi the Sun and its  atmosphere. When  we talk of the diameter of the Sun, we are  referring-to  the diameter of  the photosphere. The temperature of  the photosphere is about 6000°C. The  innermost layer of  the Sun is its core where its energy is produced through nuclear reactions. There are other layers between  the core and the photosphere which we will not describe here.  

Like the Sun's body, the solar atmosphere too has several layers. The outermost layer of  the Sun's atmosphere is called the corona. Normally, the corona cannot be s&n  due to the brilliance of  the photosphere. However, if  it is seen during a total solar eclipse, it is visible in its full. The corona extends all the way.upto the Earth's orbit and even beyond.