Vim tias qhov qhib ntawm ob sab ntawm E yog qhov tsawg tshaj plaws, qhov kev daws teeb meem ntawm tib neeg lub qhov muag yog qhov kev sim siab tshaj plaws.
Lub kaum sab xis ntawm qhov muag uas lub qhov muag ib txwm muaj peev xwm paub qhov txawv qhov me tshaj plaws (los yog qhov txawv ntawm qhov ze tshaj ob lub ntsiab lus) yog hu ua qhov tsawg kawg nkaus ntawm qhov pom, thiab qhov tsawg kawg nkaus lub qhov muag feem ntau yog lub kaum sab xis ntawm qhov pom. Ntawm qhov deb ntawm 5 meters, qhov qhib nruab nrab ntawm sab sauv thiab sab qis ntawm kab 1.0 E ntawm daim ntawv qhia qhov muag tsuas yog ib feeb ntawm lub qhov muag lub kaum sab xis (qhov qhib ntawm C ntawm daim duab qhov muag yog tib yam ). Lub kaum sab xis ntawm qhov pom ntawm qhov khoom me tshaj plaws (lossis ob lub ntsiab lus uas qhov txawv ntawm qhov ze tshaj plaws) yog hu ua qhov tsawg kawg nkaus lub kaum sab xis ntawm qhov pom, thiab qhov tsawg kawg nkaus ntawm qhov pom ntawm qhov muag feem ntau yog lub kaum sab xis ntawm ib feeb. Ntawm qhov deb ntawm 5 meters, qhov qhib nruab nrab ntawm sab sauv thiab sab qis ntawm kab 1.0 E ntawm daim ntawv qhov muag tsuas yog ib feeb ntawm lub qhov muag lub kaum sab xis (qhov qhib ntawm C ntawm daim ntawv qhov muag yog tib yam ).