A. 1 meter
B. 2 meter
C. ½ meter
D. ¼ meter
Submitted by: Rizwan Ayub Saadi
The power of a lens (P) is defined as the reciprocal of its focal length (f) in meters, measured in diopters (D).
So, if the power of the lens is one diopter, then its focal length is 1 meter.
Related Mcqs:
- 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
C. f1f2/f2+f1
D. f1f2/f1-f2 - Two convex lenses of equal focal length f are placed in contact the resultant focal length of the combination is______________?
A. zero
B. focus
C. 2 f
D. f/2 - Dioptre power of an concave lens of 10 cm focal length is_______________?
A. 10 dioptre
B. 10 dioptre
C. 1 / 10 dioptre
D. 1 / 10 dioptre - A convex lens acts as a diverging lens if the_________________?
A. object is beyond C
B. if the object is with in C
C. if the object is within f
D. both B and C - Unit of power of a lens is________________?
A. meter
B. watt
C. diopter
D. horsepower - The power of a concave lens is_______________?
A. real
B. virtual
C. positive
D. negative - The minimum distance between an object and its real image in a convex lens is_____________?
A. 2 f
B. 2.5 f
C. 3f
D. 4f - A wire obeys Hooks law is of length 11 when it is in equilibrium under a tension F1. Its length becomes 12 when the tension is increased to F2. The energy stored in the wire during this process is____________________?
A. (F1+F2) (121+122)
B. (F1+F2) (122-112)
C. (F1+F2) (12-11)
D. (F1+F2) (12-11) - 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
D. virtual - A point where the incident parallel rays of light converge or appear to diverge after passing through a lens is called______________?
A. center of curvature
B. focus
C. optical center
D. aperture
