5: Which of the following statements is true? ( (a) In order to determine the parameters in a transformer, we can use a wattmeter to provide a measurement of the

average power. (b) The permeability can be expressed as u = B*H. (c) The magnetic field intensity can be expressed as H = F*l = NI*1. \text { (d) In a magnetic circuit, the induced voltage can be expressed by } E=\frac{d \Phi}{N d t}