Why the power factor is low in the open circuit test?

explain the efficiency of tuned circuits as frequency delective circuits in paragraph form

Q-1-a) From the circuit in the Figure-1, determine the DC-bias operation Parameters: (i) IB (ii) Ic (iii) le (iv) VBE (v) VB (vi) Vc (vii) VCE (viii) Ve (Figure-1) Rg= 380kN,Rc= 1kQ B = 100, VBB = Vcc=12V RB ww. + BE BB Q-1-b) Describe briefly the input / output characteristics and application of Common Emitter BJT Configuration ww

Ts switching frequency of the buck type dc dc converter with an input voltage of 100 v is determined as 10 kHz. For the situation where the output voltage is requested by the engineer to be 60v, which of the following is wrong. A) None B) Duty (working ratio-D) should be taken as 0.6. C) If a coil of L = 2mh is used for this converter that will operate in the design criteria specified in the question, the uninterrupted operating limit value of the coil current will be approximately 16.6 A. D) When Duty 0.6 is taken, when a load of R = 6 ohms is connected at the output, the average value of the input current becomes approximately 16.6 A. E) In order to maximize the uninterrupted operation limit value of the coil current, the engineer who has to use only one coil for the design in the question should update the output voltage value in the design criterion to 40 V.