The strength of a magnetic field around a wire carrying a current of 20 A is 0.004 T. What is the strength of the magnetic field if the current is changed to 40 A?

Question

0.002 T
0.004 T
0.006 T
0.008 T

Answer 1

The strength of the magnetic field (\(B\)) around a wire carrying a current (\(I\)) is directly proportional to the current. This relationship can be described by the formula:

\[ B \propto I \]

If the current is doubled from 20 A to 40 A, the magnetic field strength will also double.

Given that the magnetic field strength at 20 A is 0.004 T, we can calculate the new magnetic field strength at 40 A as follows:

\[ B_{new} = 2 \times B_{old} = 2 \times 0.004, T = 0.008, T \]

So the strength of the magnetic field when the current is changed to 40 A will be 0.008 T.