The usual electrosurgical apparatus contains an oscillator that produces a high-frequency current of frequencies above 500,000 cycles per second (500 khz). two electrodes are connected to the device. the large electrode is placed beneath the patient, and the "active" second electrode is sterilized before use. the purpose of the current is to raise the temperature of a small part of tissue so as to coagulate it, boil the tissue fluid, or char the tissue [4]. the machine may be used in different ways.

listed below are some of these medical techniques:

electrocoagulation: electrodes are in direct contact, and the heat in the tissues causes coagulation.
electrodesiccation: the active electrode is held a very short distance from the tissue. this causes a spark to jump from the electrode to the tissue, which in turn causes evaporation of moisture with coagulation, penetrating more deeply than when in contact.
electrohemostasis: the bleeders are clamped with a hemostat in the usual manner. the electrode is touched to the clamp, and the dehydration and coagulation take place under the clamp.
electric cutting: the fine tungsten wire makes a minute arc (a continuous spark or tiny flame) just before touching the tissue. this cuts the tissue and seals off the blood vessels. the arc separates the wire from the tissue so that the wire does not actually touch it. that is, the arc does the cutting rather than the wire.
electrocautery is especially valuable in surgery of the brain, prostate gland, and the liver [4].

in which of the following medical techniques is the active electrode in direct contact with the tissue?

group of answer choices

a、electrodessication

b、electrocoagulation

c、electrohemostais

d、electric cutting