# 28 Lecture

## PHY101

### Midterm & Final Term Short Notes

## Currents and Circuits

Currents and circuits are fundamental concepts in the study of physics. Current refers to the flow of charged particles, such as electrons, in a conductor. Circuits, on the other hand, refer to the paths that these charged particles take through

**Important Mcq's**

Midterm & Finalterm Prepration

Past papers included

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**In a simple circuit consisting of a resistor and a battery, what happens to the current if the resistance is doubled?**

a) The current doubles

b) The current is halved

c) The current remains the same

d) The current becomes zero

**Answer: b) The current is halved**

**What is the unit of electric current?**

a) Joule

b) Coulomb

c) Watt

d) Ampere

**Answer: d) Ampere**

**In a parallel circuit, what happens to the total resistance when additional resistors are added?**

**a) The total resistance decreases**

b) The total resistance increases

c) The total resistance remains the same

d) The total resistance becomes zero

**Answer: a) The total resistance decreases**

**What is the relationship between voltage, current, and resistance in a circuit?**

a) V = IR

b) I = VR

c) R = IV

d) V = RI

**Answer: a) V = IR**

**In a circuit with a battery and a single resistor, what happens to the current if the voltage of the battery is increased?**

a) The current increases

b) The current decreases

c) The current remains the same

d) The current becomes zero

**Answer: a) The current increases**

**What is the role of a capacitor in a circuit?**

a) To store energy in the form of electric charge

b) To increase the resistance of the circuit

c) To reduce the resistance of the circuit

d) To act as a switch

**Answer: a) To store energy in the form of electric charge**

**In a circuit with multiple resistors in series, what happens to the total resistance when the resistors are replaced with ones of lower resistance?**

a) The total resistance increases

b) The total resistance decreases

c) The total resistance remains the same

d) The total resistance becomes zero

**Answer: b) The total resistance decreases**

**What is the unit of electric potential difference?**

a) Volt

b) Joule

c) Coulomb

d) Watt

**Answer: a) Volt**

**In a series circuit, what happens to the current as it passes through each component?**

a) The current increases

b) The current decreases

c) The current remains the same

d) The current becomes zero

Answer: b) The current decreases

**What is the relationship between power, voltage, and current in a circuit?**

a) P = VI

b) V = PI

c) I = PV

d) P = IV

Answer: a) P = VI

**Subjective Short Notes**

Midterm & Finalterm Prepration

Past papers included

Download PDF
**What is an electric current, and what are its units?**

**Answer**: Electric current is the flow of electric charges through a conductor. It is measured in amperes (A).

**What is Ohm’s Law, and how is it used in circuits?**

**Answer:** Ohm’s Law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to its resistance. It is commonly used to calculate the resistance, current or voltage of a circuit.

**What is the difference between AC and DC current?**

**Answer: **AC (alternating current) changes direction periodically, while DC (direct current) flows in only one direction.

**What is a circuit diagram, and how is it useful?**

**Answer: **A circuit diagram is a graphical representation of an electrical circuit that shows how the various components are connected. It is useful for understanding the functioning of the circuit and troubleshooting it if any problem arises.

**What is a series circuit, and how does it differ from a parallel circuit?**

**Answer: **In a series circuit, the components are connected in a single loop, while in a parallel circuit, the components are connected in separate branches.

**What is a resistor, and how does it affect the flow of current in a circuit?**

**Answer:** A resistor is an electrical component that resists the flow of current in a circuit. It is used to regulate the amount of current flowing through a circuit.

**What is a capacitor, and how is it used in a circuit?**

**Answer: **A capacitor is an electrical component that stores electric charge. It is commonly used in circuits to block DC current and pass AC current.

**What is an inductor, and how does it affect the flow of current in a circuit?**

**Answer:** An inductor is an electrical component that stores energy in a magnetic field. It is used to oppose changes in current flow in a circuit.

**What is a diode, and what is its purpose in a circuit?**

**Answer:** A diode is an electrical component that allows current to flow in only one direction. It is used to regulate the flow of current in a circuit and prevent reverse current.

**What is a transistor, and how is it used in electronic devices?**

**Answer: **A transistor is an electrical component that is used to amplify or switch electronic signals. It is a fundamental building block of modern electronic devices such as computers and smartphones.