Since 1990, hand-held mobile phones have been used as communication devices. Mobile phones have gone through a lot of design changes over the years. Do online research and discuss the major changes in mobile phone designs in the last 20 years.

An ideal otto cycle with air as the working fluid has a compression ratio of 8. the minimum and maximum temperatures in the cycle are 300 k and 1340 k. use constant specific heats at room temperature to determine (a) the amount of heat transferred to the air during the heat- addition kj/kg, (b) the thermal efficiency, and (c) the thermal efficiency of a carnot cycle ope limits. process, in rating between the same temperature