[" 8.On making a coil of copper wire of length "ell" and coil "],[" radius "r" ,the value of self inductance is obtained as "],[" L.If the coil of same wire,but of coil radius "r/2," is "],[" made,the value of self inductance will be- "],[[" (A) "2L," (B) "L],[" (C) "4L," I "(D)L/2]]