Elements of Remote Sensing

1. 'A' and 'B' are two towers of equal height diametrically opposite on either side of the nadir point, at 3 km and 5 km distances. Which one of the following statements is correct?

1. Height displacement of A will be less than that of B
2. Height displacement of B will be less than that of A
3. Height displacement of A and B is equal
4. Height displacement of A and B will be towards each other

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2. A passive sensor uses:

1. Sun as the source of energy
2. Flash light as a source of energy
3. Its own source of energy
4. None of these

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3. A perfectly black body:

1. Is a diffuse emitter
2. Absorbs all the radiations of every wave lengths
3. Emits power of every wave length
4. All the above

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4. A reduction of nitrogen nutrient in plants:

1. Affects leaf colour
2. Reduces pigment concentration
3. Increase the visible reflectivity
4. All of these

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5. 'A time varying electric field produces a magnetic field.' This phenomenon is called:

1. Hertz's law
2. Ampere Maxwell's law
3. Faraday's law
4. Kirchoff's law

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6. According to the Snell's law if an electromagnetic wave is incident in a medium (refractive index n1) on another medium (refractive index m2);

1. The angle of incidence is equal to the angle of refraction
2. The angle of refraction r) is given by sin i
3. Both (a) and (b)
4. Neither (a) nor (b)

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7. An Electromagnetic wave falls on to a boundary between two losses less homogeneous media with different refractive indices, a part of the wave is reflected back to the incident medium and the rest is transmitted on to the second media. This phenomenon is known as:

1. Fresnel reflection
2. Fresnel refraction
3. Snell's law
4. None of these

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8. Coherence of two electromagnetic waves takes place if their phase difference is:

1. Constant in time
2. Constant in space
3. Constant in time and space
4. None of these

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9. Consider the following statements regarding the satellite imaging:
1. The satellite orbit is fixed in the inertial space
2. During successive across-track imaging, the earth rotates beneath the sensor
3. The satellite images a skewed area
Which one of the following statements is/are correct?

1. 1, 2, 3
2. 1, 3
3. 2, 3
4. 1, 2

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10. Critical angle of electromagnetic radiation takes place if

1. Angle of incidence is equal to angle of refraction
2. Angle of incidence is greater than the angle of refraction
3. Angle of incidence is equal to 90°
4. Angle of refraction is equal to 90°

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