The answer to both is D. Here's why:
For the first, whenever motion changes in a magnetic field, it causes electrons to move. Electricity, which is needed to power a lightbulb, is just a term for movement of these electrons. Electrons aren't created, they're always there in the wire. It's just that the permanent magnet gets them to move, which produces electricity.
For the second, it is very similar to the first. A magnet won't cause any electric current at rest, it always requires motion in order to produce an electric current. If you keep both of those in mind, it should help in the future. Hope this helps!
Which is an example of a compound? sand, gold, water, or iodine? well, the answer is water, water is a compound.
Answer:
Mass of proton neutron and electron
Protons, neutrons, and electrons: Both protons and neutrons have a mass of 1 amu and are found in the nucleus. However, protons have a charge of +1, and neutrons are uncharged. Electrons have a mass of approximately 0 amu, orbit the nucleus, and have a charge of -1.
Explanation:
Hope this helps :)
Answer:
1) The power needed to process 50 ton/hr is 135.4 HP.
2) The void fraction of the bed is 0.37.
Explanation:
1) For this type of milling operations, we can estimate the power needed for an operation according to the work index (Ei), the passing size of the circuit feed (F80) and the passing size of the product (P80).
We assume the units of Ei are kWh/t.
The equation that relates this parameters and the power is (size of particles in μm):

The power needed to process 50 ton/hor is

2) The density of the packed bed can be expressed as

being f the fraction and ρ the density of every fraction. We know that the density of the void is 0 (ρv=0) and that fv=1-fs (the sum of the fractions ois equal to the total space).
Then we can rearrange

The void fraction of the bed is 0.37.