\textbf{167.} In a converging lens, the distance between the object and the image is $20\,\text{cm}$ and the magnification is $0.5$. If the object is placed $20\,\text{cm}$ from the lens, by how much will the magnification change?
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(1) $0.2$ \hspace{1cm} (2) $0.4$ \hspace{1cm} (3) $0.6$ \hspace{1cm} (4) $0.8$
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