The minimum magnifying power of an astronomical telescope is \(40\). If the length of the telescope is \(205\) cm, then the focal length of its field lens is:
1. \(5\) cm
2. \(200\) cm
3. \(40\) cm
4. \(140\) 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 astronomical telescope has angular magnification of \(40\) in its normal adjustment. If focal length of eyepiece is \(5\) cm, the length of the telescope is:
1. \(190\) cm
2. \(200\) cm
3. \(205\) cm
4. \(210\) cm
1. | \(60\) cm | 2. | \(120\) cm |
3. | \(30\) cm | 4. | \(180\) cm |
The condition of minimum deviation is achieved in an equilateral prism kept on the prism table of a spectrometer. If the angle of incidence is \(50^{\circ}\), the angle of deviation is:
1. \(25^{\circ}\)
2. \(40^{\circ}\)
3. \(50^{\circ}\)
4. \(60^{\circ}\)
An object is placed \(20\) cm in front of a concave mirror of a radius of curvature \(10\) cm. The position of the image from the pole of the mirror is:
1. \(7.67\) cm
2. \(6.67\) cm
3. \(8.67\) cm
4. \(9.67\) cm
The angle of minimum deviation for a glass prism of refractive index \(\mu = \sqrt{3}\) equals the refracting angle of the prism. The angle of the prism is:
1. \(30^{\circ}\)
2. \(60^{\circ}\)
3. \(90^{\circ}\)
4. \(45^{\circ}\)
The angle of a prism is \(A\) and one of its refracting surfaces is silvered. Light rays falling at an angle of incidence \(2A\) on the first surface return through the same path after suffering reflection at the second (silvered) surface. The refractive index of the material is:
1. \(2\sin{A}\)
2. \(2\cos{A}\)
3. \(\frac{1}{2}\cos{A}\)
4. \(\tan{A}\)
The correct statement is:
1. | The intermediate image in a compound microscope is real, erect and magnified |
2. | Intermediate image in a compound microscope is real, inverted, but diminished |
3. | Intermediate image in a compound microscope is virtual, erect and magnified |
4. | Intermediate image in a compound microscope is real, inverted and magnified |
A ray of light is incident on an equilateral glass prism placed on a horizontal table as shown. For minimum deviation, a true statement is:
1. | \(PQ\) is horizontal |
2. | \(QR\) is horizontal |
3. | \(RS\) is horizontal |
4. | Either \(PQ\) or \(RS\) is horizontal |