A beam of light converges at a point P. A concave lens of focal length 16 cm is placed in the path of this beam 12 cm from P. The location of the point, from the lens, at which the beam would now converge is

Question

A beam of light converges at a point P. A concave lens of focal length 16 cm is placed in the path of this beam 12 cm from P. The location of the point, from the lens, at which the beam would now converge is (A) 48 cm (B) 45 cm (C) 80 cm (D) 90 cm

Tardigrade Admin · Accepted Answer

Here, u=+12cm,f=-16 cm=v=? By lens equation (1/f)=(1/v)-(1/u) Substituting the values (1/-16)=(1/v)-(1/12) (1/v)=(1/12)-(1/16)=(4-3/48)=(1/48) v=+48 cm The image of virtual object P forms at P at a distance of 48 cm from lens.

Q. A beam of light converges at a point P. A concave lens of focal length 16 cm is placed in the path of this beam 12 cm from P. The location of the point, from the lens, at which the beam would now converge is

48 cm

45 cm

80 cm

90 cm

Here, u=+12cm,f=−16cm=v=? By lens equation f1​=v1​−u1​ Substituting the values −161​=v1​−121​ v1​=121​−161​=484−3​=481​ v=+48cm The image of virtual object P forms at P at a distance of 48 cm from lens.