Question

U= -10 cm
V=-20cm
f = ?​

Answer 1

Given,

u = -10 cm

v = -20 cm

To Find,

f = ?

Solution,

$</p><p>\sf \rightarrow \quad \dfrac{1}{f} = \dfrac{1}{v} + \dfrac{1}{u} \\ \\ \sf \rightarrow \quad \frac{1}{f} = - \frac{1}{20} - \frac{1}{10} \\ \\ \sf \rightarrow \quad \frac{1}{f} = \frac{ - 1 - 2}{20} \\ \\ \sf \rightarrow \quad \frac{1}{f} = \frac{ - 3}{20} \\ \\ </p><p>$

So,

f = $\sf - \dfrac{20}{3}<strong> </strong>\:$ cm

Answer 2

Answer:

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