[{"id":9178,"question":"A beam of light enters air from water.Which of the following characteristics of light will not change in water","choices":[{"text":"Frequency","value":"A"},{"text":"Wavelength","value":"B"},{"text":"Velocity","value":"C"},{"text":"Amplitude","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9177,"question":"Refractive index of material depends upon","choices":[{"text":"Nature of material","value":"A"},{"text":"Wave length","value":"B"},{"text":"Temperature","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9176,"question":"Two lenses of power +12 and -2 diopters are placed in contact the power of combination is","choices":[{"text":"10 diopters","value":"A"},{"text":"8 diopters","value":"B"},{"text":"6 diopters","value":"C"},{"text":"12 diopters","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9175,"question":"If the cover of a red book is observed in monochromatic blue light,It will appear","choices":[{"text":"White","value":"A"},{"text":"Red","value":"B"},{"text":"Black","value":"C"},{"text":"Blue","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9174,"question":"A tourmaline crystal is being used as an analyzer In one complete rotation of the crystal the number of excitation will be","choices":[{"text":"0","value":"A"},{"text":"1","value":"B"},{"text":"2","value":"C"},{"text":"4","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9173,"question":"A convex lens is dipped in a liquid whose refractive index is equal to the material of the lens. Then its focal length will become","choices":[{"text":"Infinite","value":"A"},{"text":"Zero","value":"B"},{"text":"Extremely small","value":"C"},{"text":"Extremely large","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9172,"question":"The ratio of the diameter of two convex lenses is the ratio of their focal lengths","choices":[{"text":"Greater than","value":"A"},{"text":"Less than","value":"B"},{"text":"Equal to","value":"C"},{"text":"None","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9171,"question":"The light signal in graded index fibre is totally confined due to","choices":[{"text":"Total inernal reflection","value":"A"},{"text":"Continuous refraction","value":"B"},{"text":"Both a and b","value":"C"},{"text":"Dispersion","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9170,"question":"A spectrometer is used to find","choices":[{"text":"Wavelength of light","value":"A"},{"text":"Refractive index of the prism","value":"B"},{"text":"Angle of minimum deviation of prism","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9169,"question":"A double convex lens act as a diverging lens when the object is","choices":[{"text":"Inside the focus","value":"A"},{"text":"Between f and 2f","value":"B"},{"text":"At the focus","value":"C"},{"text":"At a large distance","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9168,"question":"The resolving power of human eye is","choices":[{"text":"1<span style=\"color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;\">°</span>&nbsp;","value":"A"},{"text":"2<span style=\"color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;\">°</span>","value":"B"},{"text":"3<span style=\"color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;\">°</span>","value":"C"},{"text":"6<span style=\"color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;\">°</span>","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9167,"question":"A fly is sitting on the objective of a telescope pointed towards the moons what effect is impacted in a photograph of the moon taken through the telescope","choices":[{"text":"The entire field of vision is blocked","value":"A"},{"text":"There is image of the fly on the photograph","value":"B"},{"text":"There is no effect at all","value":"C"},{"text":"There is the reduction in intensity of the image","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9166,"question":"The magnifying power of a simple microscope can be increased if we use eye piece of","choices":[{"text":"Higher focal length","value":"A"},{"text":"Smaller focal length","value":"B"},{"text":"Higher diameter","value":"C"},{"text":"Smaller diameter","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9165,"question":"In a simple microscope if the final image is located at infinity then its magnifying power is","choices":[{"text":"25/f","value":"A"},{"text":"25","value":"B"},{"text":"f/25","value":"C"},{"text":"[1 + (25/f)]","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9164,"question":"The object is placed at the principle focus of a simple microscope if the focal length of the lens is 2cm what is the magnifying power of the microscope","choices":[{"text":"13.5","value":"A"},{"text":"12.5","value":"B"},{"text":"Infinity","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9163,"question":"An object is placed between two parallel mirrors the number of images formed is","choices":[{"text":"2","value":"A"},{"text":"4","value":"B"},{"text":"8","value":"C"},{"text":"Infinite","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9162,"question":"The bottom of a container filled with liquid appear slightly raised because of","choices":[{"text":"Refraction","value":"A"},{"text":"Interference","value":"B"},{"text":"Diffraction","value":"C"},{"text":"Reflection","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9161,"question":"The brilliance of diamond is","choices":[{"text":"Entirely due to refractive index","value":"A"},{"text":"Entirely due to total internal reflection","value":"B"},{"text":"Partly due to total internal reflection","value":"C"},{"text":"None of the above","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9160,"question":"What is the time taken by light to travel 4 mm in a material of refractive index 3","choices":[{"text":"4 x 10<sup>-11</sup>&nbsp;s","value":"A"},{"text":"2&nbsp;x 10<sup>-11</sup>&nbsp;s","value":"B"},{"text":"16&nbsp;x 10<sup>-11</sup>&nbsp;s","value":"C"},{"text":"8&nbsp;x 10<sup>-11</sup>&nbsp;s","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9159,"question":"If the power of a lens is 4 diopters then is focal length is","choices":[{"text":"20 cm","value":"A"},{"text":"25 cm","value":"B"},{"text":"50 cm","value":"C"},{"text":"400 cm","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9158,"question":"Television signal are converted into light signals by","choices":[{"text":"Decoder","value":"A"},{"text":"Transistor","value":"B"},{"text":"Photodiode","value":"C"},{"text":"Optical fibre","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9157,"question":"In spectrometer the function of collimator is to produce","choices":[{"text":"Diverging beam of light","value":"A"},{"text":"Converging beam of light","value":"B"},{"text":"Parallel beam of light","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9156,"question":"The wavelength of refractive wave in a denser medium is","choices":[{"text":"Same as that of the incident wave","value":"A"},{"text":"Become smaller than the incident","value":"B"},{"text":"Becomes greater than the incident wave","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9155,"question":"The minimum distance between a source and the screen for which a real image is possible with a convex lens is","choices":[{"text":"Its focal length","value":"A"},{"text":"Twice the focal length","value":"B"},{"text":"Four times the focal length","value":"C"},{"text":"Square of the focal length","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9154,"question":"An object is placed at a distance 18 cm from a convex lens. The image is formed at a distance of 9 cm the focal length of the lens is","choices":[{"text":"6 cm","value":"A"},{"text":"9 cm","value":"B"},{"text":"10 cm","value":"C"},{"text":"18 cm","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9153,"question":"Alexander graham bell transmits a voice message via a","choices":[{"text":"Beam of light","value":"A"},{"text":"Telescope","value":"B"},{"text":"Compound microscope","value":"C"},{"text":"Mirror","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9152,"question":"In an optical fibre the speed of light is","choices":[{"text":"Directly proportional to its refractive","value":"A"},{"text":"Inversely proportional to its refractive inedex","value":"B"},{"text":"Independent of refractive index","value":"C"},{"text":"Directly proportional to square of refractive index","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9151,"question":"To get high resolving power for a telescope one should use","choices":[{"text":"Objective of large aperture","value":"A"},{"text":"Objective of large focal length","value":"B"},{"text":"Eye piece of large focal length","value":"C"},{"text":"Eye piece of small focal length","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9150,"question":"The frequency of light ray is 6 x 10<sup>14</sup> Hz. The frequency when it propagates in a medium of refractive index 1.5 will be","choices":[{"text":"6 x 10<sup>14</sup> Hz","value":"A"},{"text":"4&nbsp;x 10<sup>14</sup>&nbsp;Hz","value":"B"},{"text":"9&nbsp;x 10<sup>14</sup>&nbsp;Hz","value":"C"},{"text":"1.67&nbsp;x 10<sup>14</sup>&nbsp;Hz","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9149,"question":"Rainbow is formed due to combination of","choices":[{"text":"Dispersion and total internal reflection","value":"A"},{"text":"Reflection and refraction","value":"B"},{"text":"Dispersion and focusing","value":"C"},{"text":"Refection and scattering","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":9148,"question":"Spectrum of sun consists of","choices":[{"text":"Bright lines","value":"A"},{"text":"Dark lines","value":"B"},{"text":"Bright bands","value":"C"},{"text":"Dark bands","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9147,"question":"Focal length of convex lens is maximum for","choices":[{"text":"Blue light","value":"A"},{"text":"Yellow light","value":"B"},{"text":"Green light","value":"C"},{"text":"Red light","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9146,"question":"Wavelength of light of frequency 100 Hz is","choices":[{"text":"2&nbsp;x 10<sup>6 </sup>m","value":"A"},{"text":"3 x 10<sup>6 </sup>m","value":"B"},{"text":"4&nbsp;x 10<sup>6&nbsp;</sup>m","value":"C"},{"text":"5&nbsp;x 10<sup>6 </sup>m","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9145,"question":"One cannot see through fog becuase","choices":[{"text":"Fog absorbs light","value":"A"},{"text":"The refractive index of fog is infinity","value":"B"},{"text":"Light suffers total reflection at the droplet in a fog","value":"C"},{"text":"Light is scattered by the droplets in fog","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9144,"question":"In young s interference experiment one slit is covered with a cellophane paper which absorbs half the intensity then","choices":[{"text":"No fringes are observed","value":"A"},{"text":"All fringes will be darks","value":"B"},{"text":"bright fringes will be less bright and dark will be less dark","value":"C"},{"text":"Bright fringes will be brighter and dark fringes will be darks","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9143,"question":"In Newton s rings the central spot appears dark due to","choices":[{"text":"Phase change","value":"A"},{"text":"Destructive interference","value":"B"},{"text":"Small eye piece of optical device","value":"C"},{"text":"Both a and b","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9142,"question":"Optically active substance are those substance which","choices":[{"text":"Produce polarization of polarized light","value":"A"},{"text":"Rotate the plane of polarization of polarized light","value":"B"},{"text":"Produce double refraction","value":"C"},{"text":"Both a and b","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":9141,"question":"Which of the following is not an application of polarization","choices":[{"text":"To reduce glare of light","value":"A"},{"text":"To check concentration sugar in solution","value":"B"},{"text":"Curtain less windows","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":9140,"question":"A diffraction grating of length 2cm has 4000 lines The grating element is","choices":[{"text":"0.5 x 10<sup>-2</sup> cm","value":"A"},{"text":"5 x 10<sup>4</sup>","value":"B"},{"text":"5&nbsp;x 10<sup>-4</sup>","value":"C"},{"text":"0.5&nbsp;x 10<sup>-4</sup>&nbsp;cm","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":9139,"question":"In Michelsons interference the movable mirror is moved and a shift of two fringes is observed then the distance moved by the mirror is","choices":[{"text":"<span style=\"color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;\">λ</span><font color=\"#000000\" face=\"Georgia\" size=\"4\"><span style=\"line-height: 23.390625px;\">/2</span></font>","value":"A"},{"text":"<span style=\"color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;\">λ</span>","value":"B"},{"text":"2<span style=\"color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;\">λ</span>","value":"C"},{"text":"None","value":"D"},{"value":"E"}],"correctAnswer":2}]