Answer:
The current is
Explanation:
From the question we are told that
The radius of the loop is
The earth's magnetic field is
The number of turns is
Generally the magnetic field generated by the current in the loop is mathematically represented as
Now for the earth's magnetic field to be canceled out the magnetic field generated by the loop must be equal to the magnetic field out the earth
=>
Where is the permeability of free space with value
=>
Answer:
Let N0 be the initial atoms of Be11
N0 / 2^1 = N0 / 2 Number of Be11 after 1 half-life
N0 / 2^2 = N0/ 4 Number of Be11 after 2 half-lives
30/13.81 = 2.17 half lives
N0 / 2^2.17 = N0 / 4.51 = .222 N0 or 22.2 % of atoms remain
Answer
Correct Answers are Mid ocean ridges are sites of seafloor spreading
and Younger ocean floor is created
Explanation
Harry H. Hess was a geophysicist. In 1960, he proposed a theory which is later became known as 'Sea Floor Spreading'. Hess discovered that the oceans were shallower in the middle. According to Hess, From Earth’s mantle molten material is continuously flowing along the crests of the mid-ocean ridges.
As soon as temperature of magma decreases, it is pushed away from the flanks of the ridges. Due to this process a younger ocean floor is created.
Hess also proposed that due to light weight of continental crust, it didn't sink back into the deep earth at trenches as did the oceanic crust.