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level: SAQs

Questions and Answers List

level questions: SAQs

Question	Answer
when a ray of light passes from a denser medium to a rarer medium , the refracted ray bends away from the normal. as the angle of incidence increases the angle of refraction also increases, and for the angle of incidence for which the angle of refraction is 90 is called critical angle.	critical angle
when a light ray is passed from a denser to rarer medium with an angle of incidence greater than the critical angle reflects back into the denser medium,obeying the laws of reflection.	total internal reflection
it is an optical illusion caused by atmospheric refraction. on a still hot day travellers on a tarred road or in desserts get the impression of pool of water on the road.	mirage
the coloured arcs or the spectrum of white light from the sun on the form of bows observed immediately after rain the formation of rainbow is combined effect of reflection ,refraction and dispersion of light in the water droplets when light from the sun falls on it.	rainbow and formation
light from the sun after dispersion from the water droplets reaches the observer after suffering 'one internal reflection' violet in the inner edge and red in outer intensity is more	primary rainbow
light from the sun after undergoing dispersion from the water droplets reaches the observer after suffering 'two internal reflections' red on the inner edge and violet on the outer fainter	secondary rainbow
at sunset or sunrise, the sun rays have to pass through a greater distance in the atmosphere. most of the shorter wavelengths are removed by scattering as scattering of light is inversely proportional to the 4th root of wavelength . and the least scattered red light reaches our eye .	reddish appearance of the sun
a convex lens of small focal length can be used to see magnified images of small objects.	simple microscope
when a star moves away from the earth with high velocity , the frequency of the light emitted by the star decreases and the wave length increases, thus its spectral lines shift towards the red end of the spectrum	red shift
when a star moves towards the earth with high velocity, the frequency of the light emitted by the star increases and the wavelength decrease. thus its spectral lines shift towards the blue end of the spectrum .	blue shift
the total electric flux through any closed surface is equal to 1/e times the net charge enclosed by that surface	Guass's law
the magnitude of the electrostatic force of attraction or repulsion between any two point charges is directly proportional to the product of the magnitude of the charges and inversely proportional to the square of the distance between them.	coulomb's law
the line integral of the magnetic field of induction B around any closed path in vaccum or air is equal to the permeability of free space in vaccum time the total current enclosed by the closed path.	ampere's law
the intensity of magnetic field of induction dB at a point due to an element is directly proportional to the length of the element, current passing through the element , sine of the angle between the element and the position vector of the point and inversely proportional to the distance between the element and the point.	biot savart's law
loops of electric current induced within the conductor by the change of magnetic field in the conductor ,according to faraday's law induction.	eddy current
induction furnaces,induction motors,eddy brakes, energy meters, speedometer, fault detection in components	advantages of eddy current
spectra of atoms having more than one electron arrangement of electrons in an orbit rate of transition of electrons fine structure of atom chemical bonding zeeman and stark effect	limitations of bohr's theory
v=R(1/n1^2-n2^2) Lymen - UV region Balmer - visible region Paschen - near the IR Bracket - in the IR Pfund - far from IR	spectral series in H atom (LBPBP)
the process of converting alternating current (AC) into direct current(DC)	rectification
the angular momentum of a moving electron is an integral multiple of h/2pi	de broglie's explanation of bohr's second postulate