1. What is Radiation Pressure?

Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. It is a result of the momentum carried by light and other electromagnetic waves.

2. How Does the Calculator Work?

The calculator uses the radiation pressure formula:

Where:

• \( P \) — Radiation pressure (Pascals)
• \( I \) — Intensity of the radiation (W/m²)
• \( c \) — Speed of light (3 × 10⁸ m/s)

Explanation: The pressure is directly proportional to the intensity of the radiation and inversely proportional to the speed of light.

3. Importance of Radiation Pressure

Details: Radiation pressure is important in astrophysics (e.g., stellar formation), solar sail technology, and laser applications. It's also a fundamental concept in quantum electrodynamics.

4. Using the Calculator

Tips: Enter the radiation intensity in W/m². The speed of light is pre-filled as 3 × 10⁸ m/s but can be modified if needed for different media.

5. Frequently Asked Questions (FAQ)

Q1: How does radiation pressure relate to photon momentum?
A: Each photon carries momentum p = E/c. The pressure is the total momentum transfer per unit area per unit time.

Q2: What are typical radiation pressure values?
A: For sunlight at Earth's orbit (~1361 W/m²), pressure is about 4.5 μPa. Laser beams can produce much higher pressures.

Q3: Does radiation pressure double for perfect reflection?
A: Yes, for perfect reflection the momentum transfer doubles, resulting in twice the pressure compared to perfect absorption.

Q4: Can radiation pressure be negative?
A: In certain metamaterials with negative refractive index, negative radiation pressure has been theoretically predicted.

Q5: How is this different from radiation force?
A: Radiation pressure is force per unit area, while radiation force is the total force on an object.