1. | \(f' = f\) |
2. | \(f'<f\) |
3. | \(f'>f\) |
4. | The information is insufficient to predict |
1. | \(X+Y\) | 2. | \(\dfrac{X +Y}{2}\) |
3. | \(X-Y\) | 4. | \(\dfrac{X -Y}{2}\) |
A plane mirror is placed at the bottom of a fish tank filled with water of refractive index \(\dfrac{4}{3}.\) The fish is at a height \(10~\text{cm}\) above the plane mirror. An observer \(O\) is vertically above the fish outside the water. The apparent distance between the fish and its image is:
1. | \(15\text{cm}\) | 2. | \(30~\text{cm}\) |
3. | \(35~\text{cm}\) | 4. | \(45~\text{cm}\) |
If \(C_1,~C_2 ~\mathrm{and}~C_3\) are the critical angle of glass-air interface for red, violet and yellow color, then:
1. | \(C_3>C_2>C_1\) | 2. | \(C_1>C_2>C_3\) |
3. | \(C_1=C_2=C_3\) | 4. | \(C_1>C_3>C_2\) |
An object is placed \(20~\text{cm}\) in front of a concave mirror of a radius of curvature \(10~\text{cm}.\) The position of the image from the pole of the mirror is:
1. \(7.67~\text{cm}\)
2. \(6.67~\text{cm}\)
3. \(8.67~\text{cm}\)
4. \(9.67~\text{cm}\)
1. | \(\frac{\sqrt{3}}{2} \) | 2. | \(1.5 \) |
3. | \(1.732 \) | 4. | \( 2\) |
A thin rod of length \(\dfrac{f}{3}\) lies along the axis of a concave mirror of focal length \(f.\) One end of its magnified, real image touches an end of the rod. The length of the image is:
1. | \(f\) | 2. | \(\dfrac{f}{2}\) |
3. | \(2f\) | 4. | \(\dfrac{f}{4}\) |
A thin equiconvex lens of power \(P\) is cut into three parts \(A,B,\) and \(C\) as shown in the figure. If \(P_1,P_2\) and \(P_3\) are powers of the three parts respectively, then:
1. | \(P_1=P_2=P_3\) | 2. | \(P_1>P_2=P_3\) |
3. | \(P_1<P_2=P_3\) | 4. | \(P_2=P_3=2P_1\) |
A medium shows relation between \(i\) and \(r\) as shown. If the speed of light in the medium is \(nc\) then the value of \(n\) is:
1. | \(1.5\) | 2. | \(2\) |
3. | \(2^{-1}\) | 4. | \(3^{-\frac{1}{2}}\) |
A person can see clearly objects only when they lie between \(50~\text{cm}\) and \(400~\text{cm}\) from his eyes. In order to increase the maximum distance of distinct vision to infinity, the type and power of the correcting lens, the person has to use will be:
1. | \(\text{convex, +2.25 diopter}\) | 2. | \(\text{concave, -0.25 diopter}\) |
3. | \(\text{concave, -0.2 diopter}\) | 4. | \(\text{convex, +0.5 diopter}\) |