Q.1.
) Electron cannot be constituent of the nucleus because [ AFMC 2010]
-
64%
a) the electron is a negatively charged particle
-
17%
b) the compton wave length of electron is larger than the size of nucleus
-
14%
c) the mass of the electron is very small as compared to the mass of the neutron or proton
-
6%
d) None of these
Q.2.
) The kinetic energy of an electron which is accelerated through a potential difference of 100V is [ AFMC 2010]
-
28%
a)6.626 × 103 watt
-
28%
b) 1.16 × 10-34 J
-
16%
c)418.6 cal
-
28%
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]
-
30%
a) 46 × 10-19 J
-
35%
b) 23 × 10-19 J
-
30%
c)36.8 × 10-19 J
-
5%
d) 9.2 × 10-19 J
Explanation
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]
-
35%
a) 9.6 × 107 C/kg
-
19%
b) 19.2 × 107 C/kg
-
42%
c)4.8 × 107 C/kg
-
4%
d)2.4 × 107 C/kg
Explanation
Q.5.
) The working of which of the following is similar to that of a slide projector? [AFMC 2008]
-
45%
a) Electron microscope
-
10%
b) Scanning electron microscope
-
45%
c) Transmission electron microscope
-
0%
d) Atomic force microscope
Q.6.
) Which of the following element has highest first ionization potential ? [ AFMC 2009]
-
32%
a) As
-
21%
b) Bi
-
16%
c)Sb
-
32%
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]
-
35%
a) band emission spectum
-
29%
b) line emssion spectum
-
24%
c) band absorption spectrum
-
12%
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]
-
11%
a)correct
-
63%
b) wrong
-
16%
c)information is insufficient
-
11%
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]
-
57%
a) (1/27) of the original value
-
7%
b) (1/9) of the original value
-
21%
c)(1/18) of the original value
-
14%
d)(1/3) of the original value
Q.10.
) A free neutron decays spontaneously into [ AFMC 2008]
-
76%
a) a proton, an electron and anti neutrino
-
19%
b) a proton, an electron and a neutrino
-
5%
c)a proton and electron
-
0%
d)a proton, and electron, a neutrino and an anti-neutrino
Explanation
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]
-
29%
a) True
-
71%
b) false
-
0%
c)may be true for perticular pressure
-
0%
d)none of the above
Q.12.
0) In compound X(n, α ) ----> 3 Li 7 , the element X is [ AFMC 2007]
-
37%
a) 2 He 4
-
21%
b) 5 B 10
-
21%
c) 5 B 9
-
21%
d) 4 Be 11
Explanation
Q.13.
) Order of e/m ratio of proton, α - particle and electron [ AFMC 2004]
-
43%
a) (e/m)p >(e/m)α > (e/m)e
-
29%
b) (e/m)e > (e/m)p > (e/m)α
-
7%
c)(e/m)α > (e/m)e > (e/m)p
-
21%
d)none of these
Explanation
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
-
16%
a) 3 → 2
-
37%
b) 5 → 4
-
32%
c)4 → 2
-
16%
d)2 → 1
Q.15.
3) In Bohr model the hydogen atom, the lowest orbil corresponds to
-
19%
a) Intial energy
-
31%
b) zero energy
-
38%
c) The minimum energy
-
12%
d)The maximum energy
Explanation
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.
-
20%
a) Z2 n2
-
40%
b) n2 / z
-
13%
c) Z2 / n
-
27%
d) n 2 / Z2
Explanation
Q.17.
) Number of spectral lines in hydrogen atom is.
-
33%
a) 6
-
27%
b) 8
-
13%
c)15
-
27%
d)infinite
Q.18.
) The nucleus which has radius one third of the radius of Cs189 is
-
27%
a) Be 9
-
18%
b) F19
-
27%
c)C12
-
27%
d)Li7
Explanation
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
-
7%
a)v / 214
-
29%
b) 4v / 214
-
43%
c)4v / 206
-
21%
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
-
15%
a) 27 R
-
31%
b) 9R
-
31%
c) 3R
-
23%
d) (27)1/2 R
Explanation
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)
-
31%
a) 16 / 7R
-
23%
b)16 / R
-
46%
c)16 / 3R
-
0%
d)16 / 5R
Explanation
Q.22.
0) The control rod in a nuclear reactor is made of
-
13%
a) uranium
-
33%
b) Cadmium
-
13%
c)plutomium
-
40%
d)grabhite
Q.23.
1) which of the following isotopes normally fissonable
-
29%
a)92 U 233
-
21%
b) 92 U 238
-
29%
c)92 U 235
-
21%
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.
-
38%
a) r0 / 2
-
31%
b) 4 × r0
-
8%
c) r0 / 4
-
23%
d) 2 × r0
Explanation
Q.25.
3) A Free neutron decays into a Proton, an electron and
-
8%
a)ν
-
31%
b) ν
-
31%
c)α
-
31%
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?
-
18%
a) Paschen
-
18%
b) Lyman
-
27%
c)Brakett
-
36%
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
-
21%
a)Zero
-
29%
b)10.2 eV
-
21%
c)6.8 eV
-
29%
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
-
23%
a) N0 /16
-
38%
b) N0 /8
-
23%
c) N0 / 4
-
15%
d) N0 / 2
Explanation
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.
-
33%
a) 4u / 238
-
50%
b) -4u / 238
-
8%
c)4u / 234
-
8%
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 )
-
21%
a) 0.2 ln 4
-
57%
b) 0.4 ln 4
-
14%
c)0.4 ln 2
-
7%
d) 0.8 ln 2
Explanation
