Answer:
when a person is not breathing
Explanation:
The electrocardiogram shows the cardiac action of the heart as a means of the sinusoidal waves. However, the waves have a different structure as they show the pumping phase, breathing and the resting phase of the heart. The waves continues to be displayed as long as there is systolic and diastolic pressure in the heart muscles. When there is no action, such as the cessation of brain activity, action ceases.
Answer:
1) A time-varying magnetic field will produce an electric field.
4) A time-varying electric field will produce a magnetic field.
Explanation:
1) A time-varying magnetic field will produce an electric field.
TRUE
time varying magnetic field will produce electric field which is given as

2) Time-varying electric and magnetic fields can propagate through space only if there is no matter in their path.
FALSE
Time varying electric field and magnetic field will induce each other and it can travel through any medium as well as it can travel without any medium also
3) Electric and magnetic fields can be treated independently only if they vary in time.
FALSE
electric field can be due to stationary charge and magnetic field due to current carrying elements so it is not compulsory to have time varying
4) A time-varying electric field will produce a magnetic field.
TRUE
Time varying electric field will produce magnetic field given as

In the left-hand rule, the field is represented by the forefinger and it is perpendicular to the motion.
<h3>Fleming’s Left-Hand Rule:</h3>
A force perpendicular to the field's direction and the direction of the current flow is experienced by a current-carrying conductor when it is exposed to an external magnetic field. According to Fleming's Left Hand Rule, if the thumb, forefinger, and middle finger are arranged in a straight line on the left hand, the thumb will point in the direction of the force experienced by the conductor, and the forefinger will point in the direction of the magnetic field, and the middle finger will point in the direction of the electric current. This rule is employed to determine the magnetic force's direction within an electric motor.
Fleming’s Left-Hand Rule are essential rules applicable in magnetism and electromagnetism. They were created by John Ambrose Fleming in the late 19th century as an easy method of determining the direction of motion in an electric motor.
Learn more about Fleming’s Left-Hand here:
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