A beam of light is incident at 60° to a plane surface. The reflected and refracted rays are perpendicular to each other. What is the R.I. of the surface:
1.1√3
2.√3
3.1/3
4.3
Posted Date:-2021-12-17 08:25:45
A blue cross on the white background is illuminated with white light and is observed through red filter. What is seen?
1.A red cross on a black background
2.A blue cross on a red background
3.A red cross on a blue background
4. A black cross on a red background
Posted Date:-2021-12-17 08:52:28
A certain far-sighted person cannot see objects closer to the eye than 100 cm. The power of the lens which will enable him to read at a distance of 25 cm will be?
1. 3D
2.1D
3.4D
4.2D
Posted Date:-2021-12-17 08:48:54
A convergent lens will become less convergent in :
1.oil
2.water
3.both of (a) and (b)
4.None of the above
Posted Date:-2021-12-17 08:26:32
A convex lens is dipped in a liquid, whose R.I. is equal to that of R.I. of material of the lens. Then its focal length will:
1. become zero
2.become infinite
3.reduce
4.increase
Posted Date:-2021-12-17 08:47:20
A double convex air bubble in water behaves as:
1. Convergent lens
2.divergent lens
3.plane slab
4.concave mirror
Posted Date:-2021-12-17 08:54:01
A point object is placed at the centre of a glass sphere of radius 6 cm 3 and RI = 32. The distance of virtual image from the surface of the sphere is :
1. 2 cm
2. 4 cm
3.6 cm
4.12 cm
Posted Date:-2021-12-17 08:44:27
A ray of light travelling in air is incident of a glass slab. The ray gets partly reflected and partly refracted. The phase difference between the reflected and the refracted waves is :
1. π/2
2.Ï€/4
3.Ï€
4.Zero
Posted Date:-2021-12-17 08:20:18
A telescope has an objective lens of 10 cm diameter and is situated at a distance of 1 km from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when seen in the light of mean λ = 5000 A is of the order of:
1.5 mm
2.5 cm
3.0.5 m
4.5 m
Posted Date:-2021-12-17 08:45:58
A thin glass (RI = 32) lens has optical power of – 5D in air. Its optical power in a liquid medium with RI = 1.6 will be:
1.-2.5 D
2.25 D
3.-ID
4. 0.625 D
Posted Date:-2021-12-17 08:27:18
ar point of a myopic eye is 40 cm. The dioptic power of a corrective lens is:
1. 40 D
2.-4 D
3.-2.5 D
4.-0.25 diopter
Posted Date:-2021-12-17 08:50:46
If a mirror is approaching you at a speed of 10 ms^1, the speed with which your image approach you is:
1.10 ms-1
2. 5 ms-1
3.20 ms-1
4.15 ms-1
Posted Date:-2021-12-17 08:22:56
On reflection from a denser medium, a light wave suffers a phase difference of:
1. π
2.Ï€/2
3.Ï€/4
4.2Ï€
Posted Date:-2021-12-17 08:28:23
Radio waves from an antenna travel with the velocity of:
1.light
2.sound
3.ultrasonics
4.supersonics
Posted Date:-2021-12-17 08:42:55
The air bubble inside water shine due to:
1.Reflection
2.Refraction
3. T.l.R.
4.None of the above
Posted Date:-2021-12-17 08:41:14
The angle of deviation for a prism is greatest for:
1.violet
2.red
3.orange
4.yellow
Posted Date:-2021-12-17 08:53:08
The angle of minimum deviation for an equilateral glass prism is 30°. Refractive index of the prism is:
1. 1√3
2.√2
3.1
4.can’t be determined
Posted Date:-2021-12-17 08:24:26
The branch of optics dealing with the formation of images using the concept of straight line propagation of light is called:
1.geometrical optics
2. physical optics
3. corpuscular optics
4.quantum optics
Posted Date:-2021-12-17 08:29:11
The phase difference between the electric and the magnetic field vectors in electromagnetic waves is
1.Ï€/4
2.Ï€/2
3.Ï€
4.Zero
Posted Date:-2021-12-17 08:19:25
The refractive indices (R.I.) of glass and water with respect to air are 3/2 and 4/3 respectively. The R.I. of glass w.r. to w ater is:
1.8/9
2.9/8
3.7/6
4.2
Posted Date:-2021-12-17 08:23:53
The RI. of the material of a prism is √2 and its refracting angle is 30°. One of the refracting surface of the prism is made a mirror. A beam of monochromatic light entering the prism from the other face retraces its path, after reflection from mirror surface. The angle of incidence on prism is:
1.0°
2.30°
3.45°
4.60°
Posted Date:-2021-12-17 08:45:14
Two lens of power -15 D and +5 D are placed in contact co-axially. The focal length of equivalent lens is:
1.-10 cm
2.-20 cm
3.+10 cm
4.None
Posted Date:-2021-12-17 08:40:12
Two points P and q are situated at the same distance from a source of light but on opposite sides. The plane difference between the light waves passing through P and q will be:
1. n
2.2n
3.Ï€/2
4.zero
Posted Date:-2021-12-17 08:18:34
Two thin lenses of focal lengths 20 cm and 25 cm are placed in contact. The effective power of the combination is:
1.45 D
2.9 D
3.19 D
4. 6 D
Posted Date:-2021-12-17 08:51:43
When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is :
1.polarized
2. of longer λ
3.of shorter λ
4.of high intensity
Posted Date:-2021-12-17 08:46:42
When a ray of light (white) enters a lens, undergoes a change is:
1.wavelength
2.velocity
3.frequency
4.both velocity and wavelength
Posted Date:-2021-12-17 08:42:02
When light travels from one medium to another, which of the following does not change?
1. frequency
2.refractive index
3.velocity
4.wavelength
Posted Date:-2021-12-17 08:31:25
Which of the following cannot be polarised?
1.radiowaves
2.transverse waves
3.sound waves
4.X rays
Posted Date:-2021-12-17 08:21:09
Which of the following is not essential for the formation of a pure spectrum?
1.parallel beam of light
2.narrow beam of light
3.screen
4.prism in the minimum deviation position
Posted Date:-2021-12-17 08:48:14
Which of-the following is not a property of light?
1.It can travel through vacuum
2.It has a finite speed
3.It requires a material medium for its propagation
4.It involve transportation energy
Posted Date:-2021-12-17 08:17:38
Which produces additional luminiscence in a fluorescent tube?
1. infra red rays
2.ultraviolet rays
3.micro waves
4.radio waves
Posted Date:-2021-12-17 08:49:58