Answer:

Explanation:
Here we can use energy conservation
As per energy conservation conditions we know that work done by external source is converted into kinetic energy of the disc
Now we have

now we know that work done is product of force and displacement
so here we have


now for moment of inertia of the disc we will have



now from above equation we will have


The magnetic field is described mathematically as a vector field<span>. This vector field can be plotted directly as a set of many vectors drawn on a grid. Each vector points in the direction that a compass would point and has length dependent on the strength of the magnetic force. </span>
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:
D
Explanation:
Cells are the smallest unit of organizaiton, followed by tissues, organs, organ systems, and then organisms themselves.