Elements Of Remote Sensing Set 3

Phase of a wave is expressed as a fraction of a period with respect to a reference ✘  Phase is usually specified by angular measure with one period being 360° ✘ The reference for finding the phase of a wave is taken from the previous passage through zero from the negative to the positive direction ✘ All of these ✔

Phytoplankton contains photosynthetically active pigment ✘ An increase of phytoplankton increases the back scattering in the green region ✘ An increase of phytoplankton absorbs the bule region rapidly ✘ An increase of phytoplankton decreases the back scattering in the green region ✔

Spectral variation ✘ Spatial variation ✘ Temporal variation ✘ All of these ✔

The first man-made satellite, Sputnik-l' was launched on 4th October, 1957 ✘ The United State's Explorer 6 transmitted the first picture of the earth in August 1959 ✘ Television Infrared Observation Satellite (TIROS) designed for meteorological observations, started systematic earth observations from space from 1, April, 1960 ✘ All of these ✔

The minimum frequency of light for which no electrons are emitted, is called threshold frequency ✘ Polarising angle of glass is 57.5°a ✘ At the polarising angle, the reflected and refracted rays are orthogonal ✘ All the above ✔

The refractive index of a medium varies according to the wavelength of the radiation ✘ The variation of the refractive index with wave length, is called dispersion ✘ The splitting of colors of white light by passing through a prism is caused due to dispersion ✘ All of these ✔

The surface defined by the locus of points having same phase, is called a wave front ✘ The wave whose surface of constant phase are parallel planes, is known as a plane wave ✘ The relative phase difference between the waves is important and not the absolute phase of a point on the wave ✘ All of these ✔

Topology describes the geometric characteristic of objects which do not change under transformations and are independent of any coordinate system ✘ Topological characteristics of an object are independent of scale measurement ✘ The three elements of topology are adjacency, containment, and connectivity ✘ All of these ✔

When the electric field oscillates in the direction of the electric vector, a plane polarised wave is formed ✘ When the electric vector is in the plane of incidence, vertical polarisation is formed ✘ When the electric vector is at right angles to the plane of incidence, horizontal polarization wave is formed ✘ All of these ✔

Hertz's law ✘ Ampere Maxwell's law ✘ Faraday's law ✘ Kirchoff 's law ✔