Ace Your Current Electricity Practice Quiz

The ampere is the SI unit for electric current, which measures the flow of charge per unit time. The other units are used for voltage, resistance, and power respectively.

Ohm's Law defines the relationship between voltage, current, and resistance as V = IR. The other formulas do not correctly represent this linear relationship.

A closed circuit has an unbroken path, allowing current to flow continuously. An open circuit, on the other hand, interrupts the flow of current.

A resistor is designed specifically to limit or reduce the flow of electric current. The other components serve different functions, such as power supply or control.

A battery supplies electrical energy to a circuit by converting stored chemical energy into electrical energy. It does not resist current flow or act as an insulator.

In a series circuit, there is only one path for the current to flow, so the same current passes through every component. While voltage drops occur across components, the current remains constant throughout the circuit.

In a parallel circuit, every branch is connected directly to the same voltage source, ensuring that the voltage across each branch is identical. However, the current may vary depending on the individual resistances of the branches.

Adding resistors in parallel provides extra pathways for the current, thereby lowering the overall resistance of the circuit. The equivalent resistance in parallel circuits is always less than the smallest individual resistor.

Electrical power is calculated using the formula P = VI, where power (P) is the product of voltage (V) and current (I). This formula directly links the energy usage of a circuit to its electrical parameters.

High resistance in a circuit limits the amount of current that can flow, as defined by Ohm's Law. This results in a lower current for a given voltage, protecting the circuit from excessive current.

Copper is widely used in electrical wiring because of its high electrical conductivity and low resistance. The other listed materials are either insulators or have very poor conductivity.

Insulators are used to prevent the flow of electrical current where it is not desired, ensuring safety and proper circuit function. They help in containing and directing current along the intended paths.

In a series circuit, all components are connected along a single path, so a failure in any one component causes the complete circuit to open. This interruption stops the flow of current throughout the entire series circuit.

A potentiometer is a variable resistor that allows users to adjust the current flowing through a circuit. It effectively changes the resistance according to the position of its wiper, thereby controlling the current.

Overloading a circuit can cause excessive current flow, which often triggers a fuse to blow. This is a protective measure designed to prevent damage to the circuit and connected devices.

In a series circuit, the equivalent resistance is simply the sum of all resistances. Adding 5Ω, 10Ω, and 15Ω gives a total resistance of 30Ω.

Using Ohm's Law (I = V/R), you divide the voltage by the resistance. With 12 V and 4 Ω, the current is 3 A.

For resistors in parallel, the equivalent resistance is calculated using 1/Req = 1/R1 + 1/R2. Two 10 Ω resistors result in an equivalent resistance of 5 Ω.

Using the power formula P = VI, the current can be found by I = P/V. Dividing 60 watts by 12 V results in a current of 5 A.

In a DC circuit, once the initially uncharged capacitor becomes fully charged, it acts as an open circuit. This causes the current to drop to zero, as no further charge can flow through the capacitor.