Popular Modern Physics Questions

*Image* Q52. how to differentiate between (1) and (4) .. they have not stated which direction to take positive axis Q43. yeh kya hai? (i mean i know logic gates.. but what are those dotted and solid lines in input? *Image* ...

1) A spectroscopic instrument can differntiate 2 close wavelengths λ and λ+Δλ if λ/Δλ = 8000. The instrument is used to study spectral lines of balmer series of hydrogen. find approx how many lines are distinguished by ...

1. A small 10W source of ultraviolet light of wavelength 99nm is held at a distance 0.1m from a metal surface. The radius of an atom of the metal is approximately 0.05nm. Find a) the average number of photons striking an atom ...

1)Two photons having a) equal wavelength have equal linear momenta b)equal energies have equal linear momenta c)equal frequencies have equal linear momenta d)equal linear momenta have equal wavelength. ans (d) now here if (d) ...

1) A point source of light is placed at the centre of curvature of a hemispherical surface.the radius if curvature is r and the inner surface is completely reflecting.Find the force on the hemisphere due to the light falling ...

Ques. A motor car is going due north at the speed of 50 km\hr. It makes a 90° left turn without changing its speed. The change in velocity is about A. 50km\hr towards west B.70 km\hr towards south west C.70km\hr towards nort ...

A:though light of a single frequncy (monochromatic) is incident on a metal,the energies of emmited photo elctrons may be diff R:The energy of electrons emmited from inside metal surface is redistributed in collisons with othe ...

what are fermions ??????????????????give examples ...

The given graphs show the variation of photoelectric current(I) with applied voltage for two different intensities of the incident *Image* ...

multi correct; in non uniform spherical shell of mass 'm' and radius R (here E is gravitational intensity) which of the following are wrong; (A) E = 0 (r<R) (B) ∫ E.dS = 0 on any closed surface inside the shell (C) E can ...

In a uranium ore sample, the ratio of U238 to Pb206 nuclei is 1/3 Assuming that all the lead present in the ore is final stable product of U238 , find the age of the ore (in 109 year) if half life of U238 is 4.5 × 109 year. ...

Q.It is given in theory books that the magnitude of photoelectric current is independent of the frequency of incident radiation . My doubt : If frequency is increased , each electron's energy increases which means some of the ...

Given a sample pf Radium-2008 having half life of 4 days. Find the probability, nucleus disintegrates after 2 half lives. A. 1 B. 1/2 C. 1.5 D. 3/4 ...

If the atom Fm257100 follows the Bohr Model & the radius of Fm257100 is n times the Bohr radius , then find n : (A) 100 (B) 200 (C) 4 (D) 1/4 ...

why ordinary light is incoherent? ...

10 gms of 57Co kept in an open container beta-decays with a half life of 270 days. The wt. of the material inside the container after 540 days will be very nearly (A) 10 g (B) 5 g (C) 2.5 g (D) 1.25 g ...

1.According to moseley, a and b in moseley's law are A)independent of the material B)dependent on the material C)a depends on the material,but b is independent of the material D)none of these 2.Photoelectric effect supports q ...

At a given instant there are 25% undecayed radioactive nuclei in a sample. After 10 seconds the number of undecayed nuclei redu ces to 12.5%. Calculate: (i) mean life of the nuclei (ii) the time in which the number of undecay ...

Q1. Light of intensity I falls on a perfectly reflecting surface at an angle θ with the normal to the surface. Find the force exerted by the light on the surface. Q2. A perfectly reflecting solid sphere of radius r is kept i ...

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27. Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate ? (a) The number of free electrons for conduction is significant only in Si and ...

in the production of x-rays,what happens if the electron that is sent hits the nucleus of the heavy metal atom. ...

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Photoelectric Effect/ Objective I:- Q.2) Two Photons having a) equal wavelengths have equal linear momenta b) equal energies have equal linear momenta c) equal frequencies have equal linear momenta d) equal linear momenta hav ...

a square loop PQRS of side 'L' is placed near an infinite current( i ) carrying wire in the same plane at a distance 'L'. now the loop is rotated about side PS by 90° . find the charge which passes through any point of the l ...

*Image* wat is d answer?? ...

find the correct statements. If Frequency and Intensity of a light source are doubled.Then a)SAtURATioN photocurrent remains almost the same. b)Maximum Kinetic Energy of photoelectrons are doubled. ...

what is spallation ,nuclear reaction and induced radioactivity ?????how to identify these all ????? ...

how photon has linear momentum as it has zero rest mass ????? ...

why nuclear force is not conservative ????????? ...