The first law of thermodynamics states that energy cannot be created or destroyed, but it can change from one form to another
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.
Answer:
3. none of these
Explanation:
The rotational kinetic energy of an object is given by:

where
I is the moment of inertia
is the angular speed
In this problem, we have two objects rotating, so the total rotational kinetic energy will be the sum of the rotational energies of each object.
For disk 1:

For disk 2:

so the total energy is

So, none of the options is correct.
Inversely proportional to its frequency. If electromagnetic radiation A has a lower frequency than electromagnetic B, then compared to B, the wavelength of A is...? - equal - shorter - longer - exactly half the length of