1. What is Solar Intensity?

Solar intensity refers to the amount of solar power received per unit area. It is affected by the angle at which sunlight strikes the surface, following Lambert's cosine law.

2. How Does the Calculator Work?

The calculator uses the solar intensity equation:

Where:

• \( I \) — Solar intensity (W/m²)
• \( I_0 \) — Solar constant (1361 W/m²)
• \( \theta \) — Zenith angle (degrees)

Explanation: The equation calculates solar irradiance adjusted for the angle of incidence, where maximum intensity occurs when the surface is perpendicular to sunlight (θ = 0°).

3. Importance of Solar Intensity Calculation

Details: Accurate solar intensity calculation is crucial for solar energy system design, agricultural planning, climate studies, and understanding Earth's energy balance.

4. Using the Calculator

Tips: Enter solar constant (typically 1361 W/m²) and zenith angle in degrees (0-90°). The zenith angle is the angle between the sun and the vertical direction.

5. Frequently Asked Questions (FAQ)

Q1: What is the solar constant?
A: The solar constant is the average solar irradiance at the top of Earth's atmosphere, approximately 1361 W/m².

Q2: Why does intensity decrease with angle?
A: As the zenith angle increases, the same amount of solar energy spreads over a larger surface area, reducing intensity per unit area.

Q3: What is the maximum possible solar intensity?
A: Maximum intensity occurs at θ = 0° (direct overhead sun), equal to the solar constant of 1361 W/m² at the top of the atmosphere.

Q4: How does atmosphere affect solar intensity?
A: The atmosphere absorbs and scatters solar radiation, reducing ground-level intensity. This calculator provides theoretical maximum values.

Q5: What are typical ground-level solar intensities?
A: On a clear day with sun directly overhead, ground-level intensity can reach about 1000 W/m² due to atmospheric absorption.