Q.1
) Electron cannot be constituent of the nucleus because [ AFMC 2010]
  • a) the electron is a negatively charged particle
  • b) the compton wave length of electron is larger than the size of nucleus
  • c) the mass of the electron is very small as compared to the mass of the neutron or proton
  • d) None of these
Q.2
) The kinetic energy of an electron which is accelerated through a potential difference of 100V is [ AFMC 2010]
  • a)6.626 × 103 watt
  • b) 1.16 × 10-34 J
  • c)418.6 cal
  • d)1.6 × 10-17 J
Q.3
) A free alpha particle and a free proton, which are seperated by a distance of 10-10 m are released. The K.E. of alpha particle when at infinite seperation is [ AFMC 2007]
  • a) 46 × 10-19 J
  • b) 23 × 10-19 J
  • c)36.8 × 10-19 J
  • d) 9.2 × 10-19 J
Q.4
) The specific charge of a proton is 9.6 × 107 C/kg . The sepcific charge of a alpha particle will be [ AFMC 2008]
  • a) 9.6 × 107 C/kg
  • b) 19.2 × 107 C/kg
  • c)4.8 × 107 C/kg
  • d)2.4 × 107 C/kg
Q.5
) The working of which of the following is similar to that of a slide projector? [AFMC 2008]
  • a) Electron microscope
  • b) Scanning electron microscope
  • c) Transmission electron microscope
  • d) Atomic force microscope
Q.6
) Which of the following element has highest first ionization potential ? [ AFMC 2009]
  • a) As
  • b) Bi
  • c)Sb
  • d)N
Q.7
4) Whight light is passed through a dilute solution of potassium permanganate. The spectrum produced by the emergent light is [ AFMC 2008]
  • a) band emission spectum
  • b) line emssion spectum
  • c) band absorption spectrum
  • d)line absorption spectrum
Q.8
) The fussion of 235 U can be triggered by the absorption of a slow netron by a nucleus. Similarily, a slow proton can also be used.This statment is [ AFMC 2007]
  • a)correct
  • b) wrong
  • c)information is insufficient
  • d)none of the above.
Q.9
) Activity of radio active sample decreases to (1/3)rd of its original value in 3 days. Then in 9 days its actvity will become [ AFMC 2008]
  • a) (1/27) of the original value
  • b) (1/9) of the original value
  • c)(1/18) of the original value
  • d)(1/3) of the original value
Q.10
) A free neutron decays spontaneously into [ AFMC 2008]
  • a) a proton, an electron and anti neutrino
  • b) a proton, an electron and a neutrino
  • c)a proton and electron
  • d)a proton, and electron, a neutrino and an anti-neutrino
Q.11
9) When a sample of solid lithum is placed in a flask of hydrogen gas then following reaction happened This statment is [AFMC 2007]
ch-19_que_no-99_img_no1.png
  • a) True
  • b) false
  • c)may be true for perticular pressure
  • d)none of the above
Q.12
0) In compound X(n, α ) ----> 3 Li 7 , the element X is [ AFMC 2007]
  • a) 2 He 4
  • b) 5 B 10
  • c) 5 B 9
  • d) 4 Be 11
Q.13
) Order of e/m ratio of proton, α - particle and electron [ AFMC 2004]
  • a) (e/m)p >(e/m)α > (e/m)e
  • b) (e/m)e > (e/m)p > (e/m)α
  • c)(e/m)α > (e/m)e > (e/m)p
  • d)none of these
Q.14
2) The transition the state n=4 to n=1 in a hydrogen like atom results in ultraviolet radiation. Infrared radition will be obtained in the transition form
  • a) 3 → 2
  • b) 5 → 4
  • c)4 → 2
  • d)2 → 1
Q.15
3) In Bohr model the hydogen atom, the lowest orbil corresponds to
  • a) Intial energy
  • b) zero energy
  • c) The minimum energy
  • d)The maximum energy
Q.16
) According to Bohr's theory the radius of electon in an orbit described by Principalquantum number n and atomic number Z, is Proportional to.
  • a) Z2 n2
  • b) n2 / z
  • c) Z2 / n
  • d) n 2 / Z2
Q.17
) Number of spectral lines in hydrogen atom is.
  • a) 6
  • b) 8
  • c)15
  • d)infinite
Q.18
) The nucleus which has radius one third of the radius of Cs189 is
  • a) Be 9
  • b) F19
  • c)C12
  • d)Li7
Q.19
7)A nucleus of 210 84 Po originally at rest emits α -particle with speed v what will bethe recoil speed of the daughter nucleus
  • a)v / 214
  • b) 4v / 214
  • c)4v / 206
  • d)v / 206
Q.20
) It the radius of a nucleus of mass number 3 is R. then the radius of a nucieus of mass mumber 81 is
  • a) 27 R
  • b) 9R
  • c) 3R
  • d) (27)1/2 R
Q.21
An electron change its Position from orbit n=4 to the orbit n=2 of an atom the wave length of emitted radition in the form of R (where R is Redburg constanst)
  • a) 16 / 7R
  • b)16 / R
  • c)16 / 3R
  • d)16 / 5R
Q.22
0) The control rod in a nuclear reactor is made of
  • a) uranium
  • b) Cadmium
  • c)plutomium
  • d)grabhite
Q.23
1) which of the following isotopes normally fissonable
  • a)92 U 233
  • b) 92 U 238
  • c)92 U 235
  • d)92 Np 289
Q.24
2) The distance of the closest abbroach of an alpha particle fired at a nuclous with kinetic energy K is rThe distemce of the closest approach when thw α- particle is fired at the same nucleus with kinetic energy 2k will be.
  • a) r0 / 2
  • b) 4 × r0
  • c) r0 / 4
  • d) 2 × r0
Q.25
3) A Free neutron decays into a Proton, an electron and
  • a)ν
  • b) ν
  • c)α
  • d)β
Q.26
4) Which of the following series in the spectrum of hydrogen alone lies in the visible region of the electro magnetic spectrum?
  • a) Paschen
  • b) Lyman
  • c)Brakett
  • d) Balmer
Q.27
5) If 13.6 eV energy is required to ionise the hydrogen atom the energy required to remove the electron form n=2 state is
  • a)Zero
  • b)10.2 eV
  • c)6.8 eV
  • d)3.4 eV
Q.28
6) It No is the original mass of the substance of halt lift 5 years, the amount of substance left after 15 years is
  • a) N0 /16
  • b) N0 /8
  • c) N0 / 4
  • d) N0 / 2
Q.29
) when U-238 nucleus originallay at rest decay by emitting an α -particle having a speed u the recoil speed of the resi-dual nucleus is.
  • a) 4u / 238
  • b) -4u / 238
  • c)4u / 234
  • d)-4u / 234
Q.30
8) At a certain instant, a radioactive sample has a decay rate of 5000 dis-interation Per minute. After 5 minute the decay rate is 1250 dis-interations Per minute. Then the decay constant is (Per-min )
  • a) 0.2 ln 4
  • b) 0.4 ln 4
  • c)0.4 ln 2
  • d) 0.8 ln 2
0 h : 0 m : 1 s