Either convection or thermal energy
The average daily annual temperature range is exceeded in places such as deserts. Deserts tend to be hotter due to the lack of water contained within them. This means that all of the sun's thermal radiation heats up the ground and air. These factors cause deserts to have above average temperatures.
Am infinite slew rate means that the changes in the output voltage occur immensely when the input voltage changes.
Slew rate is measurement of the response of an operational amplifier. For an ideal operational amplifier, time delay is negligible. Hence it has an infinite slew rate.
In simpler terms it means that it can provide output voltage simultaneously with the input voltage changes.
Hope this helps :)
