Question

4. What is the focal length of a lens of number +2?

Answer 1

mirror.

The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power.

Answer 2

$\huge{\underline{\underline{\mathfrak{\purple{♡Hëya \: Mäte♡}}}}} \\ \\ </p><p>\huge{\underline{\mathscr{Answer}}} \purple{ \implies}$as we know,

P=1/f

2=1/f

f=1/2

$<marquee><strong>hope</strong><strong> </strong><strong>it</strong><strong> helps</strong><strong>☻</strong></marquee>$