The half life of radium is about 1600 year. Of 100 gram of radium existing now, 25g will remain unchanged after
Options
(a) 4800 year (b) 6400 year (c) 2400 year (d) 3200 year
In the reaction ₉₂U²³⁴→₈₇Y²²², how many α-particle and β-particles are emitted respectively?
Options
(a) 3,5 (b) 5,3 (c) 3,3 (d) 3,1
Correct Answer:
3,1
Explanation:
Change in A = 234 – 222 = 12
which of the following can not be emitted by radioactive substances during their decay?
Options
(a) Electrons (b) Protons (c) Neutrinos (d) Helium nuclei
Correct Answer:
Protons
Explanation:
No explanation available. Be the […]
A nucleus with mass number 220 initially at rest emits an α-particle. If the Q-value of the reaction is 5.5 MeV, calculate the kinetic energy of the α-particle
Options
(a) 4.4 MeV (b) […]
A nucleus of mass number 220, initially at rest, emits an α-particle. If the Q-value of the reaction is 5.5 MeV, then the energy of the emitted α-particle will be
Options
(a) 4.8 […]
Which of the following atoms has the lowest ionisation potential?
Options
(a) ₈O¹⁶ (b) ₇N¹⁴ (c) ₅₅Cs¹³³ (d) ₁₈Ar⁴⁰
Correct Answer:
₅₅Cs¹³³
Explanation:
No explanation available. Be the first to write the explanation […]
In which of the following systems will the radius of the first orbit (n=1) be minimum?
Options
(a) Single ionised helium (b) Deutron atom (c) Hydrogen atom (d) Doubly ionised lithium
Correct Answer:
Doubly […]
If t₁ ̷ ₂ is the half-life of a substance, then t₃ ̷ ₄ is the time in which
Options
(a) substance decays 1/2 (b) substance decays (3/4)th (c) substance remains 1/2 (d) […]
If the half-life of a material is 10 yr, then in what time, it becomes 1/4th part of the initial amount
Options
(a) 15 yr (b) 20 yr (c) 25 yr (d) 30 […]
A radiactive substance emits 100 beta particles in the first 2s and 50 beta particles in the next 2s. The mean life of the sample is
Options
(a) 4 s (b) 2 s […]
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