# How to calculate dA of a hemisphere.

• physiker99
In summary, the conversation is discussing the differences between dA and dV and how boundaries for integrations are determined. It is explained that dS is the infinitesimal area element of a sphere and its direction is radial, which is why there is a component for v_r. dS can be divided into two parts, with the first part being the base of the rectangular area and the second part being the height.
physiker99
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dS is the infinitesimal area element of a sphere in this case. It is given by
$$dS=R^2\sin{\theta}d\theta d\phi$$

Its direction is radial, that's why you have the component $$v_r$$ in the second step.

$$dS$$ can be thought of as 2 parts. The first part is $$R\sin{\theta}d\phi$$, which can be thought of as the base of the rectangular area. The second part is $$R d\theta$$, which is the height of the rectangular area.

## 1. What is the formula for calculating the surface area of a hemisphere?

The formula for calculating the surface area of a hemisphere is 2πr2, where r is the radius of the hemisphere.

## 2. How do you find the radius of a hemisphere?

The radius of a hemisphere can be found by dividing the diameter of the hemisphere by 2.

## 3. Are there any other methods for calculating the surface area of a hemisphere?

Yes, you can also use the formula π2 + 2πr2 to calculate the surface area of a hemisphere.

## 4. How is the surface area of a hemisphere related to its volume?

The surface area of a hemisphere is directly proportional to its volume. As the volume increases, the surface area also increases.

## 5. Can the formula for calculating the surface area of a hemisphere be used for other shapes?

No, the formula for calculating the surface area of a hemisphere is specific to a hemisphere shape. Other shapes have their own formulas for calculating surface area.

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