COMBINATION OF LENSES

Four combinations of two thin lenses are given in List- I. The radius of curvature of all curved surfaces is r and the refractive index of all the lenses is 1.5. Match lens combinations in List-I with their focal length in List-II and select the correct answer using the code given below the lists.

Shashank went to the optician to get his eyes checked. He observed that the doctor combined two lenses and put these in front of his eyes so that he could see clearly. The powers of the two lenses used in the combination were -3 D and 4 D. What type of lens will the combination of lenses be?

Shashank went to the optician to get his eyes checked. He observed that the doctor combined two lenses and put these in front of his eyes so that he could see clearly. The powers of the two lenses used in the combination were -3 D and 4 D. Which of these will be the focal length of the combination of lenses Shashank has to wear?

Shashank went to the optician to get his eyes checked. He observed that the doctor combined two lenses and put these in front of his eyes so that he could see clearly. The powers of the two lenses used in the combination were -3 D and 4 D. Which of the two lenses can form a real image?

A point ofject 'O' lies in front of the lens as shown in figure. Find the final position of image formed by the combined lenses.

A combination of two thin lenses with focal lengths f_(1) and f_(2) respectively forms and image of distant object at distance 60cm when lenses are in contact. The position of this image shifts by 30 cm towards the combination when two lenses are separated by 10 cm . The corresponding values of f_(1) and f_(2) are