Question

In electronic circuits, resistances are used to control the
(A) voltage
(B) current
(C) inductance
(D) none of these

Answer 1

In electronics, the very basic law which shows the relation of the resistance is Ohm’s law. This law shows the relation between the current, voltage and the resistance. By using this law, the solution of this question can be determined.

Complete step by step solution:
Ohm’s law states that current flowing in any circuit is directly proportional to the voltage or potential difference between two points. $V = IR$, here, $V$ is the voltage or potential difference, $I$ is the current and $R$ is the resistance. The voltage is directly proportional to the current when the resistance is constant.

Now the resistance is given as $R = \dfrac{V}{I}$, the resistance is directly proportional to the voltage and inversely proportional to the current. Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in terms of ohms $\Omega$. By the resistance, $R = \dfrac{V}{I}$, for the constant voltage or potential difference, if the current in the circuit increases the resistance in the circuit decreases. If the current in the circuit decreases the resistance in the circuit increases.

The electrical resistance of an electrical conductor is the opposition to the passage of an electric current through that conductor; the inverse quantity is electrical conductance, the ease at which an electric current passes. Electrical resistance shares some conceptual parallels with the mechanical notion of friction. The SI unit of electrical resistance is also ohms $\Omega$.

Hence, the option (B) is the correct answer.

Note: For the constant voltage supply, the resistances in the circuit are used to control the current in the circuit. Every material which has some resistance to the current flow. If the material does not allow the current to pass, so the material has high resistance and is said to be insulators.