" A choke coil has "

[" Which of the following "],[" statements are correct in "],[" the case of choke coil? "],[" A) Choke coil works on the "],[" principle of wattless current "],[" B) A choke coil has high "],[" inductance and low "],[" resistance "],[" C) A choke coil is preferred "],[" to a rheostat in ac circuit as "],[" it consumes almost zero "],[" power "],[" D) Choke coil is used to "],[" control both ac and de "]

The current in the choke coil decreasing at the rate of 3 A//s and choke coil has inductance 3 H. Then induced e.m.f. across coil is

The power factor of choke coil is

The power factor of choke coil is