Answer:
1) joule
2)

3)

Step-by-step explanation:
1) Luminosity is the amount of light emitted (measured in Joule) by an object in a unit of time (measured in seconds). Hence in SI units luminosity is expressed as joules per second (
), which is equal to Watts (
).
This amount of light emitted is also called radiated electromagnetic power, and when this is measured in relation with time, the result is also called radiant power emitted by a light-emitting object.
Therefore, if we want to calculate luminosity the Joule as a unit will be used.
2) Work
is expressed as force
multiplied by the distane
:
Where force has units of
and distance units of
.
If we input the units we will have:
This is 1Joule (
) in the SI system, which is also equal to

3) The formula to calculate the percent error is:

Where:
is the experimental value
is the accepted value

This is the percent error