Answer:
B. Cathode Ray Tube
Explanation:
In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a negatively charged particle, which was later named the electron.
To solve this problem it is necessary to apply the concepts related to electromotive force or induced voltage.
By definition we know that the induced emf in the loop is equal to the negative of the change in the magnetic field, that is,
Where A is the area of the loop, B the magnetic field and t the time.
Replacing with our values we have that
Therefore the thermal energy produced is given by
The thermal energy produced in the loop is