Question

Which from the following is a scalar? (A) Electric current (B) Velocity (C) acceleration (D) Electric field

Short answer

Option (A) Electric current is the scalar quantity among the given options, as it only has magnitude and does not have a specific direction.

Step-by-step solution

Analyze Option (A) Electric current

Electric current is the flow of electric charge through a conductor or circuit. It is measured in Amperes (A) and only has a magnitude, with no specific direction. Therefore, electric current is a scalar quantity.

Analyze Option (B) Velocity

Velocity is a measure of how fast an object is moving in a particular direction. It has both magnitude and direction, so it's a vector quantity, not a scalar.

Analyze Option (C) Acceleration

Acceleration is the rate of change of velocity with time. Since velocity is a vector quantity, acceleration is also a vector, as it involves both magnitude and direction. So, acceleration is not a scalar.

Analyze Option (D) Electric field

Electric field is a vector quantity that represents the force felt by a charged particle in a given area. It has both magnitude (Newtons per Coulomb, N/C) and direction. Thus, electric field is not a scalar.

Identify the scalar quantity

From our analysis of each option, we can conclude that Option (A) Electric current is the scalar quantity among the given options.

Key concepts

Electric Current

Electric current is a fundamental concept in electronics and physics. It represents the flow of electric charge and is typically carried by electrons moving through a conductor, such as a metal wire. The unit of measure for electric current is the Ampere (A). A key point for understanding current is that it has a magnitude but no inherent direction in its definition.
Think of it like water flowing through a pipe - you know how much water is flowing (magnitude), but for electric current, we don't consider which direction. Because of this, electric current is known as a scalar quantity.

• It measures how much charge passes through a point in the circuit.
• There are two types: direct current (DC), where flow is constant, and alternating current (AC), where flow alternates directions.

Understanding electric current is crucial for practical applications, such as designing circuits or troubleshooting electrical systems. By treating it as a scalar, calculations can ignore direction and focus on the amount of flow.

Electric Field

The electric field describes how electric forces are distributed in space due to the presence of electric charges. If you place a charged particle in an electric field, it will experience a force. Mathematically, an electric field is a vector quantity. This means it has both a magnitude (often measured in Newtons per Coulomb, N/C) and a direction.
Imagine the electric field as an invisible force field around a charged object.
The field radiates outward and can cause other charged particles within it to move.

• The direction of the electric field is defined as the direction a positive charge would move if placed within the field.
• Its magnitude tells you how strong the force is.

Understanding the electric field is essential for explaining how forces act at a distance on charged objects, and it is a fundamental concept in electromagnetism.

Velocity and Acceleration

Velocity and acceleration are core concepts in physics that describe motion. Velocity measures how fast something is moving and in which direction. For example, a car traveling at 60 km/h north has both a speed and a direction, making velocity a vector quantity.
On the other hand, acceleration describes how quickly the velocity of an object changes over time. If a car speeds up, slows down, or changes direction, it accelerates.

• Velocity has both magnitude and direction. Its unit of measure is usually meters per second (m/s).
• Acceleration is also a vector quantity, defined as the change in velocity per unit of time. Often measured in meters per second squared (m/s²).

By understanding these quantities, we can predict and describe the motion of objects in a variety of contexts, from simple free-falling balls to complex planetary orbits.