In a resistor with a resistance of 9 ohms connected to a current source with an EMF of 4 V

| September 17, 2021 | education

In a resistor with a resistance of 9 ohms connected to a current source with an EMF of 4 V, the current is 0.4 A. Calculate the short-circuit current.

R = 9 ohms.

I = 0.4 A.

EMF = 4 V.

Ikor -?

For a closed loop, Ohm’s law is valid, which we express by the formula: I = EMF / (R + r), where I is the current in a closed circuit, EMF is the electromotive force of the current source, R is the resistance of the outer part of the circuit, r is the resistance of the current source.

R + r = EMF / I.

r = EMF / I – R.

r = 4 V / 0.4 A – 9 ohm = 1 ohm.

When the external resistance of the circuit R = 0, then the value of the current I reaches the maximum possible value. This state of the circuit is called a short circuit.

The short-circuit current Icor will be determined by the formula: Icor = EMF / r.

Icor = 4 V / 1 Ohm = 4 A.

Answer: the current strength, with a short circuit, will reach the value Icor = 4 A.



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