Physics can demand that you start with a specific result and make general rules. Not reading the text and not solving exercises makes understanding almost impossible. It also involves a lot of math which most people do not like.
Explanation:
It is given that,
Length of wire, l = 0.53 m
Current, I = 0.2 A
(1.) Approximate formula:
We need to find the magnitude of the magnetic field made by the current at a location 2.0 cm from the wire, r = 2 cm = 0.02 m
The formula for magnetic field at some distance from the wire is given by :


B = 0.000002 T

(2) Exact formula:


B = 0.00000199 T
or
B = 0.000002 T
Hence, this is the required solution.
<u>Answer</u>: The potential difference across the resistor is 12 volts.
<u>Explanation:</u>
To calculate the potential difference cross the resistor, we use Ohm's Law. This law states that the potential difference across two wires is directly proportional to the current flowing through that wire.
Mathematically,

Where,
V = potential difference = ?V
I = Current flowing = 1.2 A
R = Resistor = 
Putting values in above equation, we get:

Hence, the potential difference across the resistor is 12 volts
One of the two daughter cells wouldn't have a nucleus, which would result in the death of that cell, if not both. Hope this helps! ❤️