Question

a doctor has prescribed a corrective lens of power +1.5 D.Find the focal length of the lens.Is the prescribed lens diverging or converging?​

Answer 1

Answer:

Explanation:

P=1/f (in meter)

Then,

1.5=1/f

f=1/1.5

f=0.67m

Convet 0.67m in cm

0.67×100

67cm

So,we have f is 67cm.

The prescribed lens is converging.

Answer 2

Answer:

$The \: power \: of \: this \: lens \: is \: positive , \\ therfore, \: this \: is \: a \: convex \: lens \: or \: \\ converging \: lens. \: now, \\ Power, p = \frac{1}{f(in \: metrs)} \\ so \: \: \: \: \: + 1.5 = \frac{1}{f} \\ or \: \: \: f = \frac{1}{ + 1.5} \: m \\ f = + \frac{1}{1.5} \times 100cm \\ \\ So, \: \: \: focal \: length \: of \: lens \: f = + \: 66.7cm$