1
AIPMT 2007
+4
-1
Out of Syllabus
Two radioactive substances A and B have decay constants 5$$\lambda$$ and $$\lambda$$ respectively. At t = 0 they have the same number of nuclei. The ratio of number of nuclei of A to those of B will be (1/e)2 after a time interval
A
$$4\lambda$$
B
$$2\lambda$$
C
1/$$2\lambda$$
D
1/$$4\lambda$$
2
AIPMT 2007
+4
-1
Out of Syllabus
In a radioactive decay process, the negatively charged emitted $$\beta$$-particles are
A
the electrons produced as a result of the decay of neutrons inside the nucleus
B
the electrons produced as a result of collisions between atoms
C
the electrons orbitting around the nucleus
D
the electrons present inside the nucleus
3
AIPMT 2007
+4
-1
In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated by an electric potential $$V$$ and then made to describe semicircular paths of radius R using a magnetic field B. If V and B are kept constant, the ratio $$\left( {{{ch\arg e\,\,on\,\,\,the\,\,ion\,\,} \over {mass\,\,of\,\,the\,\,ion}}} \right)$$ will be proportional to
A
1/R2
B
R2
C
R
D
1/R
4
AIPMT 2007
+4
-1
A nucleus $${}_Z^AX$$ has mass represented by M(A, Z). If Mp and Mn denote the mass of proton and neutron respectively and B.E. the binding energy in MeV, then
A
B.E. = [ZMp + (A $$-$$ Z)Mn $$-$$ M(A, Z)]c2
B
B.E. = [ZMp + AMp $$-$$ M(A, Z)]c2
C
B.E. = M(A, Z) $$-$$ ZMp $$-$$ (A $$-$$ Z)Mn
D
B.E. = [M(A, Z) $$-$$ ZMp $$-$$ (A $$-$$ Z)Mn]c2
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