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Numerical Aperture Question & Answers

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This article lists 25 Numerical Aperture MCQs for engineering students. All the Numerical Aperture Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, or interviews, or professionals who would like to brush up on the fundamentals of Numerical Aperture.

The numerical Aperture (NA) of an optical system is a number i.e., dimension less. It is known for the characterization of angles over various ranges. Based on the ranges defined the system can emit or accept light. It has a property that it remains constant for the beam moving from one to another material such that at its interface refractive power is absent.

In microscopy, the concept of numerical aperture describes the cone acceptance for the objective. In Optics its purpose is to describe the angles range that decides the light i.e., incident on fiber & gets transmitted along. The lens power of resolving is determined based on the Numerical aperture.

In various areas of Optics and Microscopy, the Numerical aperture is determined by NA = n sinθ. Where n is the medium's refractive index and θ is the Acceptance angle. The angular aperture in the air for the lens is approximated to twice its value. For a particular point of image or object, the numerical aperture is measured and it is dependent on that point.

A lens with a large value of NA is capable of visualizing the finest details compare to the less that has a small NA. Larger NA lenses can collect more quantity of light and provides the image brighter but the field depth is shallow. In optic discs, NA determines the pit size. Increase in objectives NA and the magnification working distances can be reduced.

1). What determines the optical fibers' ability to collect the light rays incident on it?

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2). How does the light get propagated in Optical Fiber?

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3). What is considered while the signal is transmitted through Optical Fiber?

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4). What relates to the angle of acceptance?

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5). Light ray traveling from denser to the rarer media makes ___________ with the axis of the fiber?

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6). Which expression determines NA of fiber?

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7). Numerical Aperture in the fiber must be______?

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8). How the NA value in fiber will be increased?

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9). To make NA high what must be ƞ1 and ƞ2?

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10). Cladding over the layered core can be removed that makes NA ________?

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Numerical Aperture MCQs for Exams

11). What affects the normalizing fiber frequency?

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12). Number of modes to propagate light inside the fibers is determined by _____________?

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13). Step-index fibers NA is __________?

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14). What is the NA for Step-index fiber in a medium?

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15). NA remains _________ when a light beam travels from one to another material?

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16). Find the θa for NA 0.607 in the medium air?

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17). What are the units of NA?

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18). Find the materials NA if the θa is 70 degrees in the water?

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19). What is the NA of the Coaxial cable with its core and cladding indexes as 2.44 & 1.2?

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20). A Fiber made of silicon with a diameter of the core is large such that it consists of core and claddings refractive indexes of 1.40 and 1.37. Find the NA of Fiber.

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Numerical Aperture MCQs for Students

21). For a step-indexed fiber, the angle of cut-off to enter light into the fiber from the air is 7.50 degrees.

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22). Objectives distance of working can be reduced if NA is ______________?

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23). Pit size is determined based on _______________?

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24). Lens is capable to visualize the details finer if the NA is __________?

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25). What determines the lens power of resolving?

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