Final answer:
Phil is exercising his expert power by advising Moira on laptop choices, as it comes from his specialized knowledge in IT.
Step-by-step explanation:
In the scenario where Phil, the head of an IT department, is giving advice to his friend Moira on which laptop to purchase for work, Phil is exercising his expert power. Expert power is a form of personal power that arises from the skills or expertise one has in a particular area, which in this case is Phil's in-depth knowledge of computers and IT. This contrasts with other forms of power such as coercive power, which relies on the threat of negative outcomes; reward power, based on the ability to administer positive rewards; or legitimate power, which stems from an official position or role.