Complete Question
The complete question is shown on the first uploaded image
Answer:
The magnetic field is 
And the direction is 
Explanation:
From the question we are told that
The magnetic field at the center is 
Generally magnetic field is mathematically represented as

We are told that it is equal to 1mT
So

From the first diagram we see that the effect of the current flowing in the circular loop is (i.e the magnetic field generated)

This implies that the effect of a current flowing in the smaller semi-circular loop is (i.e the magnetic field generated)

and for the larger semi-circular loop is

Now a closer look at the second diagram will show us that the current in the semi-circular loop are moving in the opposite direction
So the net magnetic field would be





Recall 
So

Using the Right-hand rule we see that the direction is into the page which is 
The cart is going left is your answer
Answer:
Here we need to make parallel connection of two 80 ohm resistors to achieve 40 ohm net resistance.
Explanation:
As we know that the resistances in series add up directly and here we are given with only the resistors of 80 Ω.
So when we connect two resistors of 80 ohm in parallel we get the resultant of 40 ohm.
Mathematically:



gives us the only combination of two resistors in parallel.
<span>An isotope is a form of a
chemical element whose atomic nucleus contains a specific number of neutrons in
addition to the number of protons that distinctively defines the element. The
nuclei of most atoms have neutrons as well as protons.</span>
Answer:
x=45
Explanation:
by taking 42 and dividing it by 14 you get 1/3, because 14 is 1/3 of 42 you can then see that the ratio is multiplied by 3. si then you can just multiply 15 by 3 to get 45