A 20 metre straight length of rectangular air conditioner ducting (made from a perfect conductor) has cross-sectional dimensions of 24 cm by 18 cm. A mobile phone is standing up near one end the ducting so that its antenna is linearly polarised parallel to the short side of the ducting. For each of the following situations, will the mobile phone signals reach the other end of the ducting? Give reasons for your answer, and explain the nature of the signal propagation in each case. 2.a.i The mobile phone is transmitting at 900 MHz. The mobile phone is dual-band and it's operation was switched to transmit at 1800 2.a.ii MHz. 2.a.iii The mobile phone is rotated so it is now orthogonal to the short side of the ducting and switched back to operating at 900 MHz.