A liquid of refractive index 1.33 is placed between two identical plano-convex lenses, with refractive index 1.50. Two possible arrangements, P and Q, are shown. The system is:
1. | divergent in P, convergent in Q | 2. | convergent in P, divergent in Q |
3. | convergent in both | 4. | divergent in both |
A ray of light falls on a prism ABC (AB=BC) and travels as shown in figure. The refractive index of the prism material should be greater than:
1. | \(4 /{3}\) | 2. | \( \sqrt{2}\) |
3. | \(1.5\) | 4. | \( \sqrt{3}\) |
To increase the magnifying power of a telescope:
1. | The focal length of the eyepiece should be increased. |
2. | The focal length of the objective should be increased. |
3. | The wavelength of light should be increased. |
4. | The aperture of the eyepiece should be increased. |
The focal length of a glass lens in air is 20 cm. If it is dipped in water , its focal length in water will be:
1. | 80 cm | 2. | 40 cm |
3. | 60 cm | 4. | 20 cm |
When a concave mirror of focal length f is immersed in water, its focal length becomes f', then:
1. | f'=f |
2. | f'<f |
3. | f'>f |
4. | The information is insufficient to predict |
An object is at a distance of 30 cm in front of a concave mirror of focal length 10 cm. The image of the object will be:
1. | smaller in size. |
2. | inverted. |
3. | between the focus and centre of curvature. |
4. | All of the above. |
To a diver inside water, the setting sun will appear at an angle (with the horizontal) of: \(\left[ \mu_w = \frac{5}{4} \right]\)
1. \(53^{\circ}\)
2. \(37^{\circ}\)
3. \(45^{\circ}\)
4. \(60^{\circ}\)
A spherical fishbowl of radius 15 cm is filled with water of refractive index . A cat standing outside in the air at a distance of 30 cm from the centre of the fishbowl is looking at the fish. At what distance from the centre would the cat appear to the fish situated at the centre?
1. | 45 cm | 2. | 30 cm |
3. | 15 cm | 4. | 25 cm |
Two convex lenses of focal length X and Y are placed parallel to each other. An object at infinity from the first lens forms its image at infinity from the second lens. The separation between the two lenses should be:
1. | X + Y | 2. | \(\frac{X + Y}{2}\) |
3. | X - Y | 4. | \(\frac{X - Y}{2}\) |
A plane mirror is placed at the bottom of a fish tank filled with water of refractive index . The fish is at a height 10 cm above the plane mirror. An observer O is vertically above the fish outside water. The apparent distance between the fish and its image is:
1. 15 cm
2. 30 cm
3. 35 cm
4. 45 cm