Which of the following can be a source of a time-varying magnetic field?
A. A permanent magnet
B. An electric field changing linearly with time
C. Direct current
D. A decelerating charged particle
E. An antenna fed with a digital signal Choose the answer according to the source paper.

Question

Which of the following can be a source of a time-varying magnetic field?
A. A permanent magnet
B. An electric field changing linearly with time
C. Direct current
D. A decelerating charged particle

E. An antenna fed with a digital signal Choose the answer according to the source paper.

G1 Physics · Accepted Answer

The source solution identifies a decelerating charge as a source of electromagnetic radiation containing time-varying electric and magnetic fields. It also states that if the electric field changes linearly with time, the corresponding magnetic-field contribution considered there is constant. Following the source key, only statement D is selected. Hence option C follows.

Which of the following can be a source of a time-varying magnetic field? A. A permanent magnet B. An electric field changing linearly with time C. Direct current D. A decelerating charged particle E. An antenna fed with a digital signal Choose the answer according to the source paper.