Question:
Tick (✓) the correct answer:
A photograph of a bacteria enlarged 50000 times attains a length of 5 cm. The actual length of bacteria is
(a) 1000 cm
(b) 10−3 cm
(c) 10−4 cm
(d) 10−2 cm
Solution:
(c) $10^{-4} \mathrm{~cm}$
Let $x \mathrm{~cm}$ be the actual length of the bacteria.
The larger the object, the larger its image will be.
Now, $\frac{x}{1}=\frac{5}{50000}=10^{-4} \mathrm{~cm}$
Hence, the actual length of the bacteria is $10^{-4} \mathrm{~cm}$.