The energy and momentum of an electron are related to the frequency and wavelength of the associated matter wave by the relation:
`E=hv, p=h/lambda`.
But while the value of `lambda` is physically significant, the value of v (and therefore the value of the phase speed `v lambda`) has no physical significance. why?

Show that the de-Broglie wavelength lambda of electrons of energy E is givne by the relation: lambda= h /(sqrt(2 m E)) .

Give relation among the speed of sound v, wavelength lambda and frequency v.

If E_1 and E_2 are independent events associated with an experiment and P(E_1capE_2)=lambdaP(E_1)P(E_2) , then what is down the value of lambda .

If E_1 and E_2=phi are any two events associated with an experiment and lambdaP(E_1capE_2)=P(E_1//E_2) , then write down the value of lambda .

When can a charge act as a source of electromagnetic wave? How are there directions of electric and magneitc field vectors, in an electromagnetic wave related to each other and to the direction of propagation of the wave? Which physical quantity, if any has the same value for waves belonging to the differnt parts of the electromangetic spectrum?

A ray of light travelling in air have wavelength lambda ,frequency v,velocity u and intensity I.If this ray enters into water,then these parameters are lambda',v',u' and I' respectively.which of the following relation is correct?

A 2 mu F capacitor 100 ohm resistor and 8 H inductor are connected in series with an a.c. source. What should be the frequency of soure for which the current drawn in the circuit is maximum? If peak value of emf of the source is 200 V, give the phase relation between voltages acorss inductor and capacitor.

A 2 mu F capacitor 100 ohm resistor and 8 H inductor are connected in series with an a.c. source. What should be the frequency of soure for which the current drawn in the circuit is maximum? If peak value of emf of the source is 200 V, What is the phase relation between voltages across inductor and resistor ?

Agreat physicist of this century (RA.M. Dirac) loved playing with numerical values of Fundamental constants of nature. This led him to an interesting observation. Dirac found that from the basic constants of atomic physics (c, e, mass of electron, mass of proton) and the gravitational constant G, he could arrive at a number with the dimension of time. Further, it was a very large number, its magnitude being close to the present estimate on the age of the universe (~15 billion years) . From the table of fundamental constants in this book, try to see if you too can construct this number (or any other interesting number you can think of). If its coincidence with the age of the universe were significant, what would this imply for the constancy of fundamental constants ?

A circular ring of radius R with uniform positive charge density lambda per unit length is located in the y z plane with its center at the origin O. A particle of mass m and positive charge q is projected from that point p( - sqrt(3) R, 0,0) on the negative x - axis directly toward O, with initial speed V. Find the smallest (nonzero) value of the speed such that the particle does not return to P ?