Answer:
Earth, Water, Air, and Fire
Answer:
Induced current, I = 0.5 A
Explanation:
It is given that,
number of turns, N = 20
Area of wire, 
Initial magnetic field, 
Final magnetic field, 
Time taken, t = 2 s
Resistance of the coil, R = 0.4 ohms
We know that due to change in magnetic field and emf will be induced in the coil. Its formula is given by :

Where





Let I is the induced current in the wire. It can be calculated using Ohm's law as :



I = 0.5 A
So, the magnitude of the induced current in the coil is 0.5 A. Hence, this is the required solution.
Answer:
a) 
b) infrared region
Explanation:
Photon energy is the "energy carried by a single photon. This amount of energy is directly proportional to the photon's electromagnetic frequency and is inversely proportional to the wavelength. If we have higher the photon's frequency then we have higher its energy. Equivalently, with longer the photon's wavelength, we have lower energy".
Part a
Is provide that the smallest amount of energy that is needed to dissociate a molecule of a material on this case 0.42eV. We know that the energy of the photon is equal to:

Where h is the Planck's Constant. By the other hand the know that
and if we solve for f we have:

If we replace the last equation into the E formula we got:

And if we solve for
we got:

Using the value of the constant
we have this:


Part b
If we see the figure attached, with the red arrow, the value for the wavelenght obtained from part a) is on the infrared region, since is in the order of 
2.7 Paper clips, or if rounded, 3 whole paper clips.
<u>Answer:</u>
Things become hot and cold because of the transfer of energy.
<u>Explanation:</u>
The energy possessed by an object or system is called thermal energy and heat is the flow of this energy. While the law of conversation of energy states that energy is not destroyed or created, it just transfers from one object to another.
When a hot object is placed in normal conditions, it transfers heat to the environment until both are at the same temperature and heat transfers from the environment to the cold objects placed in normal conditions.