alleryStart learning →A telescope objective has diameter 2.5 m. Its angular resolution at $\lambda = 5500$ Å is approximately:
- $2.7 \times 10^{-7}$ rad (~0.06 arcsec)
- $2.7 \times 10^{-3}$ rad
- $1.0$ arcsec
- $5.5 \times 10^{-10}$ rad
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Correct answer: A. $2.7 \times 10^{-7}$ rad (~0.06 arcsec)
$\theta = 1.22\lambda/D = 1.22 \times 5.5 \times 10^{-7}/2.5 \approx 2.68 \times 10^{-7}$ rad ≈ 0.06 arcsec.
Larger apertures give better angular resolution.