Question

whta is power of a lens ? what does this sign (+ve or -ve) indicates ?

Answer 1

#️⃣*️⃣The power of a lens is its ability to bend light – the greater the power the greater the refraction of light.

The power of a lens is also related to the focal length by the following formula: 
$\bold{D}$$\bold{= \frac{1}{f}}$

Power of a lens is measured in Dioptres (D).#️⃣*️⃣

#️⃣*️⃣A “plus” (+)  sign in front of the number means you are farsighted, and a “minus” (-) sign means you are nearsighted. These numbers represent diopters, the unit used to measure the correction, or focusing power, of the lens your eye requires. Diopter is often abbreviated "D."#️⃣*️⃣

MAY THIS HELP U MY FRND!!!♥️♥️♥️♥️☺️✌️❤️❤️

Answer 2

$\huge\textbf{Answer}$

» What is power of lens ?

1 Diopter is the power of lens. It is defined as reciprocal of focal length.

1 D = $\dfrac{1}{f}$

» What does the sign (+ve or -ve) indicates ?

Positive sign (+ve) indicated that lens is convex leans or converging leans.

Negative sign (-ve) indicates that lens is concave lens or diverging lens