Explanation:
We have,
Surface area, 
The current varies wrt time t as :
(a) At t = 2 seconds, electrical charge is given by :
(b) Current is given by :
Instantaneous current at t = 1 s is,
(c) Current is, 
Current density is given by electric current per unit area.
Therefore, it is the required explanation.
Answer:
Explanation:
Ruler. A steel ruler aids the measurement and layout of straight lines. The ruler, also called "straightedge" or "straight-edged ruler," is a long, thin strip of wood, metal or plastic marked with increments of measurement.
Measuring Tape. The modern measuring tape's roughly palm-sized casing contains a coiled strip of metal marked with increments of measurement. The metal strip, called "tape," attaches to a spring which automatically retracts the tape into the casing following use.
Walking Tape Measure. The walking tape measure, also called "surveyor's measure," records the distance traveled by a wheel. An operator pushes the measure's wheel, similar to a bicycle wheel, by a handle as an attached ticker box displays feet or meters in the same format as a car's odometer.
Laser Measure. The laser measure offers point and shoot distance measurement. In its most basic form, a laser measure is a hand-held electronic device with a digital display.
Well a superconductor is a metal that acts strangely when cooled down to a certain temperature and a semiconductor and on the flip side a semiconductor<span>, is a material that has a conductivity somewhere between that of a conductor and an insulator. that is pretty much what i know i hope this helps</span>
