How can electric charges be used to create a magnetic field?

a.
a magnetic field forms around a moving electric charge, so an electric current can be used to make a magnetic field.

b.
it is not possible to create a magnetic field using electric current; a magnetic field can only be created from another magnetic field.

c.
a magnetic field forms around a stationary electric charge, so an electric current can be used to make a magnetic field.

d.
a magnetic field forms around a dipolar electric charge, so an electric current can be used to make a magnetic field.

an energy transformation flow diagram is shown

where is it ?

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form

prndulum needs thread, weight clock to time swings