surely; certainly; necessarily; fixed; a certain (extent etc); given; particular[cedict]
是
shìㄕˋ
is; are; am; yes; to be[cedict]
磁力
(n) magnetism; magnetic force[edict]
作用
zuò yòngㄗㄨㄛˋ ㄩㄥˋ
to act on; to affect; action; function; activity; impact; result; effect; purpose; intent; to play a role; corresponds to English -ity, -ism, -ization[cedict]