A convex lens of focal length 40 cm a concave lens of focal length 40 and a concave lens of focal length 15 cm are placed in contact. The power of this combination of are placed in contact. The power of this combination in diopters isA. `+1.5`B. `-1.5`C. `+6.67`D. `-6.67`

A convex lens of focal length 40 cm a concave lens of focal length 40

1.	A convex lens of focal length 40 cm a concave lens of focal length 40 and a concave lens of focal length 15 cm are placed in contact. The power of this combination of are placed in contact. The power of this combination in diopters isA. `+1.5`B. `-1.5`C. `+6.67`D. `-6.67`
Answer» Correct Answer - D `(1)/(F)=(1)/(f_1)+(1)/(f_2)+(1)/(f_3)` `=(1)/(40)+(1)/(-40)+(1)/(-15)=-(1)/(15)` `P=(100)/(F(cm))=-(100)/(15)=-(20)/(3)=-6.67D`

Discussion

No Comment Found

Related InterviewSolutions

Two convex lenses of focal length `f_1` and `f_2` are mounted coaxially separated by a distance. If the power of the combination is zero, the distance between the lenses isA. `|f_1-f_2|`B. `f_1+f_2`C. `(f_1f_2)/(|f_1-f_2|)`D. `(f_1f_2)/(f_1-f_2)`
if `mu_2=._au_g=(3)/(2),mu_3=._au_(omega)=(4)/(3)`, magnitude of radii of carvature of lens are 10 cm and 20 cm find focal length of lens if rays are incident from (a) air and (b) water,
A thin lens of focal length + 12 cm is immersed in water `(mu = 1.33).` What is its new focal length ?
A lens forms a sharp image on a screen. On inserting a parallel sided glass slab between the lens and the screen, it is found necessary to move the screen a distance `d` away the lens in order for the image to be sharp again. If the refractive index of the material of the slab is `mu`, the thickness of the slab isA. `mud`B. `(d)/(mu)`C. `(mu-1)/(mu)d`D. `(mud)/(mu-1)`
A real image of an object is formed by a conex lens at the bottom of an empty beaker. The beaker is now filled with a liquid of refractive index 1.4 to a depth of 7 cm. In order to get the image again at the bottom the beaker shoud be movedA. downward by 2 cmB. upward by 2 cmC. downward by 3 cmD. upward by 3 cm
A thin convergent glass lens `(mu_g=1.5)` has a power of `+5.0D.` When this lens is immersed in a liquid of refractive index `mu_1,` it acts as a divergent lens of focal length `100 cm.` The value of `mu_1` isA. `(4)/(3)`B. `(3)/(2)`C. `(5)/(3)`D. `2`
Focal length of a convex lense in air is `10cm`. Find its focal length in water. Given that `mu_g=3//2` and `mu_w=4//3`.A. 2.5 cmB. 5 cmC. 20 cmD. 40 cm
A point object `O` is kept at a distance `OP=u` The radius of curvature of the spherical surface APB is `CP=R` The refractive index of the media are `n_1` and `n_2` which are as shown in the diagram . Then, (A) if `n_1gtn_2`, image is virtual for all values of u (B) if `n_2=2n_1` image is virtual when `Rgtu` (C) The image is real for all values of `u`, `n_1` and `n_2` here, the correct statements is/areA. only (B)B. both (A) and (B)C. only (A)D. (A),(B) and (C)
The graps shows the variation of magnification `m` produced by as convex lens with the image distance `v`. The focal length of the lens isA. `(b)/(c)`B. `(c)/(b)`C. `a`D. `a,(b)/(c)`
A convex lens of focal length 40 cm a concave lens of focal length 40 and a concave lens of focal length 15 cm are placed in contact. The power of this combination of are placed in contact. The power of this combination in diopters isA. `+1.5`B. `-1.5`C. `+6.67`D. `-6.67`

A convex lens of focal length 40 cm a concave lens of focal length 40 and a concave lens of focal length 15 cm are placed in contact. The power of this combination of are placed in contact. The power of this combination in diopters isA. `+1.5`B. `-1.5`C. `+6.67`D. `-6.67`

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment