A
a_(2)
, oriented solenoidal coil with 1000 turns per meter has a liameter of 2 cm and is 20 cm long. It is filled with an iron bar with
a\mu _(R)=4^(**)10^(4)\mu _(0)
of the same size. The iron has a density of
7.87(g)/(c)m^(3)
. Choose the most complete answer for the minimum current that is required to keep the iron bar inside the solenoid in the earth's gravitational field of
-9.8(m)/(sec^(2)a_(q))
[in other words, so that it will not fattl? Gravily is in the -
a_(2)
direction. 4/-0.45 Amperes 1.0.4 Amperes 4 Amperes -A Amperes 4.4 Amperes -0.1. Amperes 1 Ampere None of these 4/-0.16 Amperes 4/-032 Amperes /- 4 Amperes 0.45 Amperes 4. 5.0.04 Anperes 1 Ampere /- 1 Ampere 4/-1.414 Ampere:
( )/(-)\sqrt(3)
Amperes 20 Amperes 10 Amperes /- 10 Amperes 1/- 20 Amperes 10-10/5 Amperee