Coil Whine is a high-pitched or high-frequency noise that can be heard from your laptop. This comes from the vibration of the electronic components when a current passes through them. This noise does not come from the speakers or the fans. This is usually caused by the coils contained in the motherboard, hard drive, GPU, and PSU. This is usually heard when gaming, video editing or any other task which requires intense CPU and GPU usage.
As some people are more sensitive to higher frequency sounds, they may find it easier to hear the high-pitch noise in quiet environments. However, this is not a hardware defect, and it is considered normal behavior.
