Question 11 MarkThe radius of curvature of a concave mirror is $24 \ cm.$ The value of its focal length will be $...............cm$Answer$12 \ cm.$View full question & answer→
Question 21 MarkThe power of converging lenses is $...............$ and the power of divergent lens is $...............$Answerpositive, negativeView full question & answer→
Question 31 MarkObjective lens in telescope is greater than the $...............$ lens.AnswereyepieccView full question & answer→
Question 41 MarkWhen lenses with focal length $+20 \ cm$ and $-30 \ cm$ are kept in contact, the power of the combination will be $...............$Answer$\frac{5}{3} \times D$View full question & answer→
Question 51 MarkIf the angle of incidence in an equilateral prism is $45^{\circ}$, then minimum deviation will be $...............$Answer$30^{\circ}$View full question & answer→
Question 61 MarkWhen a lens made of a material of refractive index $1.5$ is placed in a liquid of refractive index $1.7,$ its focal length will $...............$AnswerincreaseView full question & answer→
Question 71 MarkSpherical aberrations in a lens is $...............$ if the total deviation over the both surfaces are uniformly distributed.AnswerminimumView full question & answer→
Question 81 MarkWhen a lens of refractive index $n$ is placed in a liquid of refractive index $n$, lens becomes $...............$AnswerinvisibleView full question & answer→
Question 91 MarkThe phenomenon of total internal reflection is observed, while the angle of incidence is $...............$ than the critical angle.AnswermoreView full question & answer→
Question 101 MarkIf the critical angle of the medium is $60^{\circ}$ then the refractive index of the medium will be $...............$Answer$n=\left(\frac{1}{\sin c}=\frac{1}{\sin 60^{\circ}}\right.$$\left.=\frac{1}{\sqrt{3} / 2}\right)=\frac{2}{\sqrt{3}}$View full question & answer→
Question 111 MarkWhen light entering from air to glass, for $...............$ colour of light critical angle will be minimum.AnswervioletView full question & answer→
Question 121 MarkWhen the light wave passes from air to water $...............$ remains unchanged.AnswerfrequencyView full question & answer→