Magnitude and amplitude are the terms representing some factors of the important factors of science, more precisely, different branches of physics. In engineering, the differences are clearly understood by the students.

Magnitude and amplitude are different quantities and cannot be interchangeably used. So here are some basic differences between magnitude and amplitude.

**Magnitude vs Amplitude**

The difference between magnitude and amplitude is that magnitude is used to define the real number or length of vectors in measurements of distances and other scalar quantities. Amplitude is mainly used in ac signals and oscillation theories. Amplitude is the measurement of the maximum vertical length of a wave on both positive and negative regions.

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Magnitude is a factor that is used to determine the value of a quantity. Magnitude is a quantity that is used to measure the real part of a number. This is a factor to determine vector quantities.

Vector quantity comprises both the magnitude and direction of a factor to be determined. It can be both positive and negative.

Amplitude is used to measure the vertical length of a sinusoidal wave. It also measures the maximum and minimum values for a periodically changing quantity.

Amplitude is a scalar quantity, which means that it has only magnitude and so not have any directions. Amplitude is a factor mainly used in ac signals, oscillation, and communication theories.

**Comparison Table**

Parameters of Comparison | Magnitude | Amplitude |
---|---|---|

Definition | It is the real number value of a quantity such as distance or displacement irrespective of direction. | It is the maximum vertical distance of a sinusoidal wave in both positive and negative. |

Properties of | It is a property of vector quantity. | It is a property that is unique to sinusoidal waves and oscillation. |

Positive or negative | It can be both positive and negative. | It is always positive. |

Used to measure | The real part of the value to a quantity. | The vertical length of a sinusoidal wave |

Scalar or vector | It is itself a part of determining the scalar or vector quantities. | It is a scalar quantity. |

**What is Magnitude?**

Magnitude is a factor that is used to determine the value of a quantity. Magnitude is a quantity that is used to measure the real part of a number. This is a factor to determine vector quantities.

Vector quantity comprises both the magnitude and direction of a factor to be determined. It can be both positive and negative.

Magnitude is s common property of all the secondary quantities in physics. The secondary quantities are divided into scalar and vector quantities. If the quantity is scalar, that means that it poses only magnitude and no direction.

If the quantity is a vector, then it has both magnitude and direction. Magnitude is the size or the value of the quantity.

The magnitude can be measure by

a = √ (a12 +a22 +a32+…..an2)

Here ‘a’ is the total magnitude of the quantity.

For example, the distance and the displacement have the same meaning that is the length between two points. But they differ as displacement is independent of direction, whereas distance has the factor of direction.

Displacement only has magnitude. The magnitude of a factor can be both positive and negative. Negative normally indicates that the magnitude is in the opposite direction.

**What is Amplitude?**

Amplitude is used to measure the vertical length of a sinusoidal wave. It also measures the maximum and minimum values for a periodically changing quantity.

Amplitude is a scalar quantity, which means that it has only magnitude and so not have any directions. Amplitude is a factor mainly used in ac signals, oscillation, and communication theories.

In communication engineering, amplitude is one of the main factors in the field of communication. The whole process of signal transfer and modern communication is based on the amplitude of a signal wave.

The amplitude is varied accordingly to change the modulation of a wave and transmit the signal to the destination. There is a type of modulation known as amplitude modulation in which the amplitude is varied to change the modulation of a wave.

If we consider x as the periodically changing quantity with time t then,

x (t) = Asin2πft

Here, A is the amplitude of a wave.

The amplitude is independent of the factor direction. The amplitude of a wave can be measured both on positive and negative sides. But the magnitude of the amplitude of a wave is always a positive quantity. The amplitude of an ideal wave is the same on both sides of the number line.

**Main Differences Between Magnitude and Amplitude**

- Magnitude is the real number value of a quantity such as distance or displaces irrespective of direction. On the other hand, the amplitude is the maximum vertical distance of a sinusoidal wave in both positive and negative.
- Magnitude is a property of vector quantity; it is the main factor to determine the vector quantity of any factors. Amplitude is a property that is unique to sinusoidal waves and oscillation.
- Magnitude can be both positive and negative, but the factor amplitude is always positive.
- Magnitude is used to identify the real part of the value to a quantity, whereas amplitude is used to measure the vertical length of a wave.
- Magnitude is itself a part to determine the scalar or vector quantities. On the other hand, the amplitude is a scalar quantity.

**References**

- https://pubs.geoscienceworld.org/ssa/bssa/article/25/1/1/115102
- https://www.worldscientific.com/doi/abs/10.1142/9789814678766_0002

Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.