Answer:
0.2129 mm
Explanation:
We have given volume of the paint = 1 gallon
Area that covers the paint 
We have to find the thickness of the fresh paint
So
So the thickness of fresh paint on the wall is 0.2129 mm
Answer:

Explanation:
We are given that
Current in wire=40 A
Magnetic field=
T( vertically downward)
We have to find the resultant magnitude of the magnetic field 29 cm above the wire and 29 cm below the wire.
According to Bio-Savart law, the magnetic field exerted by the wire at distance R is given by

We have R=29 cm=
1 m=100 cm
Substitute the values in the given formula

The resultant magnetic field is given by

Substitute the values then we get


The resultant magnitude of magnetic field is same above and below the wire as it is at same distance.
The resultant magnitude of the magnetic field 29 cm below the wire=
Hence, the resultant magnitude of the magnetic field 29 cm above the wire=
Answer: A piston-filling fountain pen has a piston — just like in a car — inside the barrel. This piston goes down to expel air or ink and then back up, pulling ink into the barrel. The typical process is very simple, assuming the pen is clean and dry: Push the piston down, expelling any air in the barrel
1. Resonance. Mechanical waves act on or through a medium, these waves can often have frequencies that are synchronized in a way that makes them act on the matter in the medium more "aggressively."