Answer:
A) Out of the page.
Explanation:
Right-hand rule points the direction of the magnetic field at any point.
<u>Top wire</u>: Current is to the left. Point your thumb to the left and curl your other fingers around the wire. The tips of the four fingers points the direction of the field at that point. In this case, out of the page.
<u>Bottom wire</u>: Current is to the right. Point your thumb to the right and curl your other fingers around the wire. The tips of the four finger points out of the page again.
So, the total field produced by both wires is directed out of the page.
Another method to figure out the direction is the mathematical method.
Use the B-field formula:

The cross product between the direction of the current and the target position gives the direction of the B-field. If the left is -x direction and downwards is the -y direction, then
for the top wire.
for the bottom wire.
Answer:
a) 0.25m
b) 5 m/s
Explanation:
When the spring is compressed both boxes are moving with the same velocity, so applying the principle of linear momentum conservation:

Now applying the principle of energy conservation:

We got that the maximum compression is 0.25m.
The earth is so round that we can run around it in five million days
Answer: An iron atom emits particles when it is struck by light (by the photoelectric effect)
Explanation:
The first atomic model was the one proposed by Jhon Dalton, according to which it is postulated that:
"Matter is made up of indivisible, indestructible and extremely small particles called atoms."
That is, <u>the atom is a solid and indivisible mass.
</u>
However, the fenomenom by which an iron atom emits particles when it is struck by light (known as the photoelectric effect) can not be explaind by this<u> indivisible atom</u> model.
To understand it better:
The <u>photoelectric effect</u> consists of the emission of electrons (electric current) that occurs when light falls on a metal surface under certain conditions.
This is possible by considering light as a stream of photons, where each of them has energy. <u>This energy is be able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a kinetic energy. </u>This means the atom is not indivisible, but it is a composition of different particles.
In fact, currently it is known that each atom is composed of a nucleus and one or more electrons attached to the nucleus, which is composed of one or more protons and typically a similar number of neutrons.