281. Image orthicon is based on
A. photoemission principle
B. photoconduction principle
C. either of the two
D. neither of the two

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282.  An image-orthicon camera target is
A. always cathode potential stabilized
B. always anode-potential stabilized
C. either C.P.S. or A.P.S.
D. none of these

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283. In an image-orthicon camera-tube, when the light intensity from a particular spot in the scene is high, the number of electrons in the return beam from the point where that particular intensity beam strikes the target is
A. hight too
B. low
C. immaterial
D. none of these

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284. A vidicon is a camera-tube
A. based on photoconductive principles and orthogonally scanned
B. based on photoconductive principles and usingselenium or antimony target material
C. based on photoemissive principle
D. that is no longer used

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285. Operational Gamma (y) of a standard vidicon is
A. unity zero
B. between 0.65 and 0.4
C. different for different tubes
D. none of these

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286. The most suitable camera-pick up tube for industrial applications is
A. Iconoscope
B. Image-orthicon
C. Standard-vidicon
D. none of these

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287. Controlling of picture and sound to be sent on air is done in
A. the production-control section
B. the central control section
C. the video and audio sections respectively
D. none of these

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