# Ch 19: Relativity & Quantum Theory in Modern Physics

### About This Chapter

## Relativity & Quantum Theory - Chapter Summary and Learning Objectives

It is often written that Einstein said everything is relative, but what does that mean? In this chapter, you can look at the general theory of relativity and learn how to apply the equation for the theory of special relativity. You'll also learn that quantum theory's explanations of light's duality as both waves and particles has led to many technological advances. Explore our lessons about relativity and quantum theory by completing this chapter, and afterwards you should be able to identify:

- Units of energy
- The difference between particles and waves
- Techniques for measuring particles and waves
- How gravity creates curves in space and time

Video | Objective |
---|---|

General Theory of Relativity: Analysis & Practice Problems | Using the general theories of relativity, solve some hypothetical problems and discuss the findings. |

Theory of Special Relativity: Definition, Equation & Quiz | Identify Einstein's special relativity theory and review related mathematical equations. |

Einstein's Special Theory of Relativity: Analysis & Practice Problems | Continue analyzing Einstein's theory and apply his theory to some sample problems. |

Nuclear Reaction: Definition, Description & Practice Problems | Explain what occurs during a nuclear reaction and solve some hypothetical problems related to this topic. |

Quantum Theory: Definition & Examples | Analyze and collaborate about the five main topics addressed within quantum theory: 1) the properties of energy; 2) the properties of elementary particles; 3) the randomness in movement of particles; 4) the inability to measure the momentum and positions of particles simultaneously; and, 5) differences between our world and the atomic world. |

The Speed of Light: Distance & Light-Years | Review how scientists have measured the speed of light, examine the relationship between the speed of light and distance, and examine the measurements for the speed of light and for light-years. |

### 1. General Theory of Relativity: Analysis & Practice Problems

After watching this video, you should be able to explain what general relativity is, list a few consequences of the theory, and solve problems involving gravitational time dilation. A short quiz will follow.

### 2. Theory of Special Relativity: Definition & Equation

This lesson will go through the main postulates of the special theory of relativity and look at a few of the consequences. The principle equations will also be introduced. A short quiz will follow.

### 3. Einstein's Special Theory of Relativity: Analysis & Practice Problems

After completing this lesson, you should be able to explain what Einstein's special theory of relativity is and use equations from the theory to solve problems. A short quiz will follow.

### 4. Quantum Theory: Definition & Examples

After watching this lesson you will be able to explain what quantum theory is, including some key principles and scenarios, and list some applications of quantum theory. A short quiz will follow..

### 5. The Speed of Light: Distance & Light-Years

This lesson will tell you what the speed of light is, what a light year is, what lookback time is, and why it is that we see many objects in space as they were a long time ago.

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### Other Chapters

Other chapters within the Fundamental Physics course

- Introduction to Physics
- Vectors in Physics
- Kinematics in Physics
- Newton's Laws in Physics
- Work, Energy, & Power in Physics
- Linear Momentum in Physics
- Rotational Motion in Physics
- Circular Motion and Gravitation in Physics
- Oscillations in Physics
- Electrical Forces and Fields in Physics
- Potential and Capacitance in Physics
- Direct Current Circuits in Physics
- Magnetism in Physics
- Waves, Sound, and Light
- Atomic and Nuclear Physics
- Fluid Mechanics in Physics
- Thermal Physics & Thermodynamics
- The Universe
- Physics Lab Experiments: Motion
- Physics Lab Experiments: Matter & Light
- Physics Lab Experiments: Electricity