An unknown substance is tested and found to have the following physical properties:
brittle
fair conductor of electricity
dull (not shiny)
the substance is most likely a
a: metal
b: metalloid
c: nonmetal
d: can not be determined without more data

Option (B) is the correct answer.

Explanation:

Metalloids are the substance which show properties of both metals and non-metals.

Some properties of metals are that they are good conductor of heat and electricity, have shiny surface, have high melting point etc.

Some properties of non-metals are that they are bad conductor of heat and electricity, they are brittle and dull, have low melting point etc.

Thus, we can conclude that an unknown substance is tested and found to have the given physical properties represents a metalloid.

false.

explanation:

this statement is false. after falling for 5 seconds, its speed will not be 100 m/s.