Dual Nature, Atoms & Nuclei · JEE Main previous year questions

2010 4 questions

1. Q512010 · 25 Apr 2010 · Shift 1

   Statement - 1 : When ultraviolet light is incident on a photocell, its stopping potential is $V_0$ and the maximum kinetic energy of the photoelectrons is $K_{\max }$. When the ultraviolet light is replaced by $X$-rays, both $V_0$ and $K_{\max }$ increase. Statement - 2 : Photoelectrons are emitted with speeds ranging from zero to a maximum value because of the range of frequencies present in the incident light.

   1. A.Statement - 1 is true, Statement - 2 is true; Statement - 2 is the correct explanation of Statement - 1
   2. B.Statement - 1 is true, Statement - 2 is true; Statement - 2 is not the correct explanation of Statement - 1
   3. C.Statement - 1 is false, Statement - 2 is true
   4. D.Statement - 1 is true, Statement - 2 is false
   Show answer

   Answer: D

2. Q522010 · 25 Apr 2010 · Shift 1

   A nucleus of mass $M+\Delta m$ is at rest and decays into two daughter nuclei of equal mass $\frac{M}{2}$ each. Speed of light is $c$. The binding energy per nucleon for the parent nucleus is $E_1$ and that for the daughter nuclei is $E_2$. Then

   1. A.$E_2=2E_1$
   2. B.$E_1>E_2$
   3. C.$E_2>E_1$
   4. D.$E_1=2E_2$
   Show answer

   Answer: C

3. Q532010 · 25 Apr 2010 · Shift 1

   A nucleus of mass $M+\Delta m$ is at rest and decays into two daughter nuclei of equal mass $\frac{M}{2}$ each. Speed of light is $c$. The speed of daughter nuclei is

   1. A.$c\frac{\Delta m}{M+\Delta m}$
   2. B.$c\sqrt{\frac{2\Delta m}{M}}$
   3. C.$c\sqrt{\frac{\Delta m}{M}}$
   4. D.$c\sqrt{\frac{\Delta m}{M+\Delta m}}$
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   Answer: B

4. Q602010 · 25 Apr 2010 · Shift 1

   A radioactive nucleus (initial mass number $A$ and atomic number $Z$ emits $3\alpha$- particles and $2$ positrons. The ratio of number of neutrons to that of protons in the final nucleus will be

   1. A.$\frac{A-Z-8}{Z-4}$
   2. B.$\frac{A-Z-4}{Z-8}$
   3. C.$\frac{A-Z-12}{Z-4}$
   4. D.$\frac{A-Z-4}{Z-2}$
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   Answer: B