Q. No.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 point source of light \(B\) is placed at a distance \(L\) in front of the centre of a mirror of width \(d\) hung vertically on a wall. A man \((A)\) walks in front of the mirror along a line parallel to the mirror at a distance \(2L\) from it as shown. The greatest distance over which he can see the image of the light source in the mirror is:
1. \(\frac{d}{2}\)
2. \(d\)
3. \(2d\)
4. \(3d\)
| 1. | \(32.75\) | 2. | \(327.5\) |
| 3. | \(0.3275\) | 4. | None of the above |
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 cm and 400 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. | Convex, +2.25 D |
| 2. | Concave, - 0.25 D |
| 3. | Concave, - 0.2 D |
| 4. | Convex, + 0.15 D |
1. \(\frac{L}{l}+1\)
2. \(\frac{L}{l}-1\)
3. \(\frac{L+1}{l-1}\)
4. \(\frac{L}{l}\)
| 1. | lies between \(\sqrt{2} \text { and } 1 \text {. }\) |
| 2. | lies between \(2\) and \(\sqrt{2} \) |
| 3. | is less than \(1\). |
| 4. | is greater than \(2\). |
| 1. | \(-10\) cm | 2. | \(20\) cm |
| 3. | \(-30\) cm | 4. | \(5\) cm |
| 1. | equal to \(\sin ^{-1}\left(\frac{2}{3}\right)\) |
| 2. | equal to or less than \(\sin ^{-1}\left(\frac{3}{5}\right)\) |
| 3. | equal to or greater than \(\sin ^{-1}\left(\frac{3}{4}\right)\) |
| 4. | less than \(\sin ^{-1}\left(\frac{2}{3}\right)\) |
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