Question 11 MarkThe radius of curvature of a concave mirror is 24 cm. The value of its focal length will be __________ cm .Answer12 cm.View full question & answer→
Question 21 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 31 MarkWhen light entering from air to glass, for __________ colour of light critical angle will be minimum.AnswervioletView full question & answer→
Question 41 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 51 MarkSpherical aberrations in a lens is __________ if the total deviation over the both surfaces are uniformly distributed.AnswerminimumView full question & answer→
Question 61 MarkThe phenomenon of total internal reflection is observed, while the angle of incidence is __________ than the critical angle.AnswermoreView full question & answer→
Question 71 MarkThe power of converging lenses is __________ and the power of divergent lens is _____________ .Answerpositive, negativeView full question & answer→
Question 81 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 91 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 101 MarkObjective lens in telescope is greater than the __________ lens.AnswereyepieccView full question & answer→
Question 111 MarkWhen a lens of refractive index $n$ is placed in a liquid of refractive index $n$, lens becomes ___________ .AnswerinvisibleView full question & answer→
Question 121 MarkWhen the light wave passes from air to water __________ remains unchanged.AnswerfrequencyView full question & answer→