Question

If a lens of power +2D is placed in contact with another lens of power - 1D, the
combination will behave like
(A) a converging lens of focal length 100 cm
B) a diverging lens of focal length 100 cm
(C) a converging lens of focal length 1 cm
(D) a diverging lens of focal length 1 cm​

Answer 1

Answer:

c

Explanation:

a converging lens of focal length 1cm

Answer 2

Answer:

If a lens of power +2D is placed in contact with another lens of power -1D then combination will behave like a converging lens of focal length 100 cm.

Explanation:

• If a lens of power +2D is placed in contact with another lens of power -1D then combination will behave like a converging lens of focal length 100 cm.

• The effective focal length is given by : $\frac{1}{f}=\frac{1}{f1} +\frac{1}{f2}$

                                                                        $=\frac{p1}{100}+ \frac{p2}{100} =f$

                                                                        f= 100cm

• Focal length is positive that is convergent lens.

If a lens of power +2D is placed in contact with another lens of power -1D then combination will behave like a converging lens of focal length 100 cm.