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

2006 6 questions

1. Q782006 · 29 Apr 2006 · Shift 1

   The threshold frequency for a metallic surface corresponds to an energy of $6.2\mathrm{eV}$ and the stopping potential for a radiation incident on this surface is $5\mathrm{V}$. The incident radiation lies in

   1. A.ultra-violet region
   2. B.infra-red region
   3. C.visible region
   4. D.$x$-ray region
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   Answer: A

2. Q792006 · 29 Apr 2006 · Shift 1

   An alpha nucleus of energy $\frac{1}{2}m{v}^2$ bombards a heavy nuclear target of charge $Ze$. Then the distance of closest approach for the alpha nucleus will be proportional to

   1. A.$v^2$
   2. B.$\frac{1}{m}$
   3. C.$\frac{1}{v^4}$
   4. D.$\frac{1}{Ze}$
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   Answer: B

3. Q802006 · 29 Apr 2006 · Shift 1

   The time taken by a photoelectron to come out after the photon strikes is approximately

   1. A.$10^{-4}\mathrm{s}$
   2. B.$10^{-10}\mathrm{s}$
   3. C.$10^{-16}\mathrm{s}$
   4. D.$10^{-1}\mathrm{s}$
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   Answer: B

4. Q812006 · 29 Apr 2006 · Shift 1

   When ${}_3{\mathrm{Li}}^7$ nuclei are bombarded by protons, and the resultant nuclei are ${}_4{\mathrm{Be}}^8$, the emitted particles will be

   1. A.alpha particles
   2. B.beta particles
   3. C.gamma photons
   4. D.neutrons
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   Answer: C

5. Q842006 · 29 Apr 2006 · Shift 1

   If the binding energy per nucleon in ${}_3^7\mathrm{Li}$ and ${}_2^4\mathrm{He}$ nuclei are $5.60\mathrm{MeV}$ and $7.06\mathrm{MeV}$ respectively, then in the reaction $$p+{}_3^7\mathrm{Li}\to 2{}_2^4\mathrm{He}$$ energy of proton must be

   1. A.$28.24\mathrm{MeV}$
   2. B.$17.28\mathrm{MeV}$
   3. C.$1.46\mathrm{MeV}$
   4. D.$39.2\mathrm{MeV}$
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   Answer: B

6. Q952006 · 29 Apr 2006 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: C