Which of the following is the poorest conductor of electricity? Calcium (Ca)
Silicon (Si)
Fluorine (F)
Sodium (Na)
Cobalt (Co)

Fluorine (F)

Explanation:

The poorest conductor of electricity from the given choices is fluorine. This is because fluorine is a non - metal.

Like other non - metals, fluorine does not conduct electricity.

Only metals are known to conduct electricity and heat readily.

Semi - metals like silicon will conduct electricity under specific condition.

The free mobile electrons in metals makes it easy for them propagate electricity

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.