Earth's magnetic field doesn't have much to do with tectonic plates. But both are caused by movement of the magma. The magnetic field is caused by electrical currents flowing in the magma, roughly parallel with the Equator. Tectonic plates move around the surface of the Earth over the liquid magma.
So I'd go with B. mantle convection currents
It becomes an ion.
Orginally, the number of electrons of an atom should be same as the number of protons, and the atom should be electrically neutral, as each proton brings a positive charge and each electron brings a negative charge. However, when an atom loses or gains electrons, the charge would be positive or negative, depending on what the change is. In this way, the atom is no longer an atom, but an ion.
The number of electrons gained or lose by an atom depends on their group number in the periodic table. They'll gain or loose the least electrons in order to have an octet of electrons (or duplet). Which means, their outermost shell electrons would be 8, or 2 for the first shell.
One exam is fluorine. It is in the group VII, it has an outer most shell electron of 7. In order to make fluoride ion, one electron is gained, so that the outer most shell will have 8 electrons. Therefore, fluoride ion has a negative charge, as one electron brings a negative charge.
D.Richer scale
Definition: Richter scale is a quantitative measure of an earthquake's magnitude (size)
Answer:
d. 10 million years
Explanation:
These are the options for the question
Choose one answer.
a. 2.5 million years
b. 5 million years
c. 15 million years
d. 10 million years
✓half-life of the radioactive substance= 5 million years
✓ Then for every 5 million years, original radioactive given (100%) percentage is reduced by factor of 1/2.
✓ 1st 5 million year; After the first 5 million years, the original radioactive is reduced as;
(100%) × 1/2 = 50% remains
✓2nd 5 million year: At 10 millions year, the 50% remaining radioactive is reduced by factor of 1/2
(50%) × 1/2 = 25% remains
Hence, at At 10 millions years 25% of the original radioactive atoms remain
.
An isotope is an element with a different number of neutrons than protons. Neutrons have mass and therfore elements can have different masses while being the same element.
