361. If an object is placed away from 2f of a converging lens then the image will be_______________?
A. real and erect
B. virtual and erect
C. real and inverted
362. Magnifying power of simple microscope______________?
A. increase with increase in focal length
B. increase with decrease in focal length
C. no effect with decrease or increase with focal length
D. list distance of distinct vision
363. The least distance of distinct vision for a normal eye is_______________?
A. 15 cm
B. 25 cm
C. 30 cm
D. 40 cm
364. If a convex lens of large aperture fails to converge the light rays incident on it to a single point, it is said to suffer from______________?
A. chromatic aberration
B. spherical aberration
C. both spherical and chromatic
365. A convex lens of focal length f1 and a concave lens of focal length f2 are placed in contact. The focal length of the combination is_____________?
A. f2 + f1
B. f2 – f1
366. In multimode step index fibre the refractive index of core and cladding is____________?
D. different with refractive index of core higher than cladding
367. Final image produced by a compound microscope is_____________?
A. real and inverted
B. real and erect
C. virtual and erect
D. virtual and inverted
368. For normal adjustment, length of astronomical telescope is______________?
A. fo + fe
B. fo – fe
C. fo / fe
D. fe / fo
369. Two convex lenses of equal focal length f are placed in contact the resultant focal length of the combination is______________?
C. 2 f
370. Least distance of distinct vision_____________?
A. increases with increase in age
B. decreases with increase in age
C. neither increases nor decreases
D. becomes infinite after 60 years