Answer:
Current, I = 1000 A
Explanation:
It is given that,
Length of the copper wire, l = 7300 m
Resistance of copper line, R = 10 ohms
Magnetic field, B = 0.1 T

Resistivity, 
We need to find the current flowing the copper wire. Firstly, we need to find the radius of he power line using physical dimensions as :




r = 0.00199 m
or

The magnetic field on a current carrying wire is given by :



I = 1000 A
So, the current of 1000 A is flowing through the copper wire. Hence, this is the required solution.
The photon can be absorbed and the energy of the photon is exactly equal to the energy-level difference between the ground state and the level d.
Note: The diagram referred to in the question is attached here as a file.
Answer:
The magnitude of the magnetic field is 
Explanation:
The magnetic field can be determined by the relationship:
...............(1)
Were I is the current flowing through the wires
The distance R from point 1 to m is calculated using the pythagora's theorem


Substituting R into equation (1)


Answer:
Honda won by 0.14 s
Explanation:
We are given that
Distance =S=200 m
Initial velocity of Honda=u=0m/s
Initial velocity of Porsche=u'=0m/s
Acceleration of Honda=
Acceleration of Porsche's=
Time taken by Honda to start=1 s

Substitute the values




Time taken by Honda=11.55 s
Now, time taken by Porsche



Total time taken by Porsche=10.69+1=11.69 s
Because it start 1 s late
Time taken by Honda is less than Porsche .Therefore, Honda won and
Time =11.69-11.55=0.14 s
Honda won by 0.14 s
I'm assuming you want the first law of thermodynamics.
The First Law of Thermodynamics states that heat is a form of energy and cannot be created or destroyed. It can, however, be transferred from one location to another and can be converted into other forms of energy.