FORESTRY
REMOTE SENSING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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what is a passive sensor?
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Sensors that rely on the reflection of the sun’s mechanical waves from the earth’s surface
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Sensors that rely on the reflection of the sun’s electromagnetic waves from the earth’s surface
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Sensors that rely on the reflection of the sun’s electromagnetic waves from the moon’s surface
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Sensors that rely on the reflection of the moon’s electromagnetic waves from the earth’s surface
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Explanation:
Detailed explanation-1: -Remote sensing instruments on satellites are called radiometers. They are designed to accurately measure electromagnetic energy radiating from the earth and atmosphere. And everything emits electromagnetic radiation. More specifically, all objects with a temperature above absolute zero emit radiation.
Detailed explanation-2: -A passive sensor is one which just ‘listens’ to what is happening. Examples include: A light sensor which detects if a light is shining on it. An infra-red sensor which detects the temperature of an object.
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