1. What is Absorptivity?

Absorptivity (α) is the fraction of incident radiation flux absorbed by a body. It represents the efficiency with which a surface absorbs incident radiation energy.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( \alpha \) — Absorptivity (dimensionless, 0 to 1)
• \( \rho \) — Reflectivity (dimensionless, 0 to 1)

Explanation: For opaque surfaces, the sum of absorptivity, reflectivity, and transmissivity equals 1. Since opaque surfaces have zero transmissivity, absorptivity equals 1 minus reflectivity.

3. Importance of Absorptivity Calculation

Details: Absorptivity is crucial in thermal engineering, solar energy applications, materials science, and building design. It determines how much radiation energy a surface will absorb, affecting temperature regulation and energy efficiency.

4. Using the Calculator

Tips: Enter reflectivity value between 0 and 1. The calculator will compute the corresponding absorptivity value.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of possible absorptivity values?
A: Absorptivity ranges from 0 (perfect reflector) to 1 (perfect absorber).

Q2: Does this formula apply to all surfaces?
A: This formula applies specifically to opaque surfaces where transmissivity is zero.

Q3: How is reflectivity measured?
A: Reflectivity is typically measured using spectrophotometers or reflectometers that compare reflected radiation to incident radiation.

Q4: What factors affect absorptivity?
A: Surface material, texture, color, temperature, and wavelength of incident radiation all affect absorptivity.

Q5: Why is absorptivity important in solar applications?
A: High absorptivity surfaces are essential for efficient solar thermal collectors as they maximize energy absorption from sunlight.