Which of the following will be a more efficient solar furnace ? (i) concave mirror of parabolic shape of short focal length, (ii) concave mirror of long focal length

Explanation

To determine which concave mirror will be a more efficient solar furnace, we need to analyze the properties of the two types of mirrors mentioned: a concave mirror of parabolic shape with a short focal length and a concave mirror of parabolic shape with a long focal length.

### Step-by-Step Solution:

1. **Understanding the Function of a Solar Furnace**:
A solar furnace uses mirrors to concentrate sunlight onto a small area, typically a blackened absorber, to generate heat. The efficiency of the furnace depends on how well the mirror can focus the sunlight.

**Hint**: Recall that the purpose of a solar furnace is to concentrate sunlight to generate heat.
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