147725
Number of nuclei of a radioactive substance at time $t=0$ are 1000 and 900 at time $t=2 s$. What will be the number of nuclei at time $t=4 \mathrm{~s}$ ?
1 810
2 800
3 790
4 700
Explanation:
A In 2 s only $90 \%$ nuclei are left behind. Thus, in next two second $90 \%$ of 900 i.e., 810 nuclei will be left behind.
BCECE-2012
NUCLEAR PHYSICS
147684
1 curie represents :
1 $3.7 \times 10^{7}$ disintegrations per second
2 $3.7 \times 10^{10}$ disintegrations per second
3 $10^{6}$ disintegrations per second
4 1 disintegrations per second
Explanation:
B 1 curie is a unit of radioactivity that represents the activity of a quantity of radioactive material disintegrations per second.
Karnataka CET-2011
NUCLEAR PHYSICS
147687
When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ nucleus, an $\alpha$-particle is emitted, then the product nucleus is
1 ${ }_{7} \mathrm{~N}^{13}$
2 ${ }_{5} \mathrm{~B}^{10}$
3 ${ }_{4} \mathrm{Be}^{9}$
4 ${ }_{7} \mathrm{~N}^{14}$
Explanation:
D When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ ${ }_{8} \mathrm{O}^{16}+{ }_{1} \mathrm{H}^{2} \rightarrow{ }_{2} \mathrm{He}^{4}+{ }_{7} \mathrm{~N}^{14}$
AIPMT- 2002
NUCLEAR PHYSICS
147697
A free neutron decays spontaneously into
1 a proton, an electron and anti-neutrino
2 a proton, an electron and a neutrino
3 a proton and electron
4 a proton, and electron, neutrino and an antineutrino
Explanation:
A $\mathrm{n} \longrightarrow \mathrm{p}+\mathrm{e}^{-}+\bar{v}$ Free neutron decays into a proton, electron and antineutrino.
147725
Number of nuclei of a radioactive substance at time $t=0$ are 1000 and 900 at time $t=2 s$. What will be the number of nuclei at time $t=4 \mathrm{~s}$ ?
1 810
2 800
3 790
4 700
Explanation:
A In 2 s only $90 \%$ nuclei are left behind. Thus, in next two second $90 \%$ of 900 i.e., 810 nuclei will be left behind.
BCECE-2012
NUCLEAR PHYSICS
147684
1 curie represents :
1 $3.7 \times 10^{7}$ disintegrations per second
2 $3.7 \times 10^{10}$ disintegrations per second
3 $10^{6}$ disintegrations per second
4 1 disintegrations per second
Explanation:
B 1 curie is a unit of radioactivity that represents the activity of a quantity of radioactive material disintegrations per second.
Karnataka CET-2011
NUCLEAR PHYSICS
147687
When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ nucleus, an $\alpha$-particle is emitted, then the product nucleus is
1 ${ }_{7} \mathrm{~N}^{13}$
2 ${ }_{5} \mathrm{~B}^{10}$
3 ${ }_{4} \mathrm{Be}^{9}$
4 ${ }_{7} \mathrm{~N}^{14}$
Explanation:
D When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ ${ }_{8} \mathrm{O}^{16}+{ }_{1} \mathrm{H}^{2} \rightarrow{ }_{2} \mathrm{He}^{4}+{ }_{7} \mathrm{~N}^{14}$
AIPMT- 2002
NUCLEAR PHYSICS
147697
A free neutron decays spontaneously into
1 a proton, an electron and anti-neutrino
2 a proton, an electron and a neutrino
3 a proton and electron
4 a proton, and electron, neutrino and an antineutrino
Explanation:
A $\mathrm{n} \longrightarrow \mathrm{p}+\mathrm{e}^{-}+\bar{v}$ Free neutron decays into a proton, electron and antineutrino.
147725
Number of nuclei of a radioactive substance at time $t=0$ are 1000 and 900 at time $t=2 s$. What will be the number of nuclei at time $t=4 \mathrm{~s}$ ?
1 810
2 800
3 790
4 700
Explanation:
A In 2 s only $90 \%$ nuclei are left behind. Thus, in next two second $90 \%$ of 900 i.e., 810 nuclei will be left behind.
BCECE-2012
NUCLEAR PHYSICS
147684
1 curie represents :
1 $3.7 \times 10^{7}$ disintegrations per second
2 $3.7 \times 10^{10}$ disintegrations per second
3 $10^{6}$ disintegrations per second
4 1 disintegrations per second
Explanation:
B 1 curie is a unit of radioactivity that represents the activity of a quantity of radioactive material disintegrations per second.
Karnataka CET-2011
NUCLEAR PHYSICS
147687
When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ nucleus, an $\alpha$-particle is emitted, then the product nucleus is
1 ${ }_{7} \mathrm{~N}^{13}$
2 ${ }_{5} \mathrm{~B}^{10}$
3 ${ }_{4} \mathrm{Be}^{9}$
4 ${ }_{7} \mathrm{~N}^{14}$
Explanation:
D When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ ${ }_{8} \mathrm{O}^{16}+{ }_{1} \mathrm{H}^{2} \rightarrow{ }_{2} \mathrm{He}^{4}+{ }_{7} \mathrm{~N}^{14}$
AIPMT- 2002
NUCLEAR PHYSICS
147697
A free neutron decays spontaneously into
1 a proton, an electron and anti-neutrino
2 a proton, an electron and a neutrino
3 a proton and electron
4 a proton, and electron, neutrino and an antineutrino
Explanation:
A $\mathrm{n} \longrightarrow \mathrm{p}+\mathrm{e}^{-}+\bar{v}$ Free neutron decays into a proton, electron and antineutrino.
147725
Number of nuclei of a radioactive substance at time $t=0$ are 1000 and 900 at time $t=2 s$. What will be the number of nuclei at time $t=4 \mathrm{~s}$ ?
1 810
2 800
3 790
4 700
Explanation:
A In 2 s only $90 \%$ nuclei are left behind. Thus, in next two second $90 \%$ of 900 i.e., 810 nuclei will be left behind.
BCECE-2012
NUCLEAR PHYSICS
147684
1 curie represents :
1 $3.7 \times 10^{7}$ disintegrations per second
2 $3.7 \times 10^{10}$ disintegrations per second
3 $10^{6}$ disintegrations per second
4 1 disintegrations per second
Explanation:
B 1 curie is a unit of radioactivity that represents the activity of a quantity of radioactive material disintegrations per second.
Karnataka CET-2011
NUCLEAR PHYSICS
147687
When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ nucleus, an $\alpha$-particle is emitted, then the product nucleus is
1 ${ }_{7} \mathrm{~N}^{13}$
2 ${ }_{5} \mathrm{~B}^{10}$
3 ${ }_{4} \mathrm{Be}^{9}$
4 ${ }_{7} \mathrm{~N}^{14}$
Explanation:
D When a deuterium is bombarded on ${ }_{8} \mathrm{O}^{16}$ ${ }_{8} \mathrm{O}^{16}+{ }_{1} \mathrm{H}^{2} \rightarrow{ }_{2} \mathrm{He}^{4}+{ }_{7} \mathrm{~N}^{14}$
AIPMT- 2002
NUCLEAR PHYSICS
147697
A free neutron decays spontaneously into
1 a proton, an electron and anti-neutrino
2 a proton, an electron and a neutrino
3 a proton and electron
4 a proton, and electron, neutrino and an antineutrino
Explanation:
A $\mathrm{n} \longrightarrow \mathrm{p}+\mathrm{e}^{-}+\bar{v}$ Free neutron decays into a proton, electron and antineutrino.
