Question

D. 'g' vanishes at centre of

Answer 1

Answer:

a. 0.8 cm

Explanation:

The distance of the object from the lens, u = 1 cm

The magnification of the lens, m = 5

The focus of a lens formula is given as follows;

$f = \dfrac{1}{\dfrac{1}{v} + \dfrac{1}{v} }$

The magnification of the lens, m = -v/u

Where;

v = The distance of the image from the lens

Therefore, we have;

v = m × u

∴ v = 5 × 1 cm = 5 cm (on the other side of the lens)

From which we get;

$f = \dfrac{1}{\dfrac{1}{1} + \dfrac{1}{5} } = \dfrac{5}{6} \approx 0.8$

The focal length ≈ 0.8 cm