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Optics part (1)

📆 September 27, 2024

Optics part (1)

Total Questions: 78

51. The technique used to transmit audio signals in television broadcasts is: [U.P.P.C.S. (Mains) 2007 I.A.S. (Pre) 1995]

Correct Answer: (b) Frequency Modulation
Solution:Frequency modulation is used to transmit audio signals in television broadcasts. Frequency modulated signals have larger bandwidth so that FM signals on the adjacent bands have neither noise nor interference issue.

52. In human eye, light rays get transformed into neural impulses at: [U.P.P.C.S. (Pre) 1997.]

Correct Answer: (c) Retina
Solution:Visual reception occurs at the retina. Retina is the light-sensitive tissue lining the back of the eye. It contains photoreceptor cells called rods( responsible for see in dark) and cones (help to see colour). These photoreceptor cells convert the incoming light rays into electrical signals (neural impulses). These neural impulses are then processed by other neurons in the retina and sent to the brain via the optic nerve, where they are interpreted as vision.

53. The image formed on retina is : [U.P.P.C.S.(pre) 1995, U.P.P.C.S.(spl)(MAINS) 2004]

Correct Answer: (c) smaller than the object but inverted
Solution:The image formed on Retina is real, inverted and smaller than the object. The signals for image formation are sent via the optic nerve to the brain, which ultimately processes the image and allows us to see. However, the image formed os Retina is inverted but on the basis of our experience, we seen a straight image.

54. Which type of image of an object is formed by eye lens of the retina ? [Chhattisgarh P.C.S.(PRE) 2015]

Correct Answer: (c) inverted and real
Solution:The image formed on Retina is real, inverted and smaller than the object. The signals for image formation are sent via the optic nerve to the brain, which ultimately processes the image and allows us to see. However, the image formed on Retina is inverted but on the basis of our experience, we seen a straight image.

55. The principle reason why it is better to have two eyes than one is that: [R.A.S./R.T.S (PRE) 1994-95]

Correct Answer: (c) It gives a man a type of vision known as mosaic vision
Solution:Human beings have stereoscopic vision (stereopsis) means having eyes at the front of their head. The two eyes are a few centimetres apart from each other. Due to this, two eyes see the same object from two slightly different angles and send two slightly different images to the brain. The brain combines these two images to build a three-dimensional picture of the object and we can judge the depth and distance of the object more accurately.

56. Direct viewing of Sun during total solar eclipse causes irreversible damage to eyes. The retinal burn is caused by which one of the following components of the sun rays? [U.P.P.C.S. (Mains) 2003]

Correct Answer: (c) Ultraviolet light
Solution:The only time that the Sun can be viewed with the naked eye is during a total eclipse when the Moon completely covers the disk of the Sun. But it is never safe to look at a partial or annular eclipse or the partial phases of a total solar eclipse without proper equipment and techniques. Failure to use proper observing method may result in permanent eye damage or severe visual loss caused by the ultraviolet (UV) radiations.

57. The colour of the star is an indication of its: [U.P.P.C.S.(pre) 2005, U.P.P.C.S.(MAINS) 2003,2008]

Correct Answer: (b) temperature
Solution:The colour of the stars reflects the age and temperature of stars. Colour is reflected from the fusion reaction which indicates the temperature. If the temperature is high, then the star is young. The star will be blue during young stage which indicates high temperature. If star is red the temperature is low.

58. Diffusion of light in the atmosphere takes place due to : [I.A.S. (PRE) 2003, U.P.P.C.S.(pre) 2021]

Correct Answer: (b) dust particle
Solution:Sunlight is the mixture of different colours. When it passes through the atmosphere it is scattered by the air molecules, particles of dust and other subtle materials which are present in the pathway.

59. Diffusion of light in the atmosphere takes place due to [Jharkhand P.C.S (PRE) 2013]

Correct Answer: (b) dust particle
Solution:Sunlight is the mixture of different colours. When it passes through the atmosphere it is scattered by the air molecules, particles of dust and other subtle materials which are present in the pathway.

60. The colour of the light is determined by its [U.P.P.C.S.(MAINS) 2014 U.P.P.C.S.(pre) 2012]

Correct Answer: (b) wavelength
Solution:The colour of light is determined by its wavelength. Different colours have different wavelengths. In the visible spectrum of light, the wavelength of red colour is largest and violet colour has the shortest wavelength.

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