Physics

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- R= 12dis/min per gm and R₀= 16dis/min per gm T_1/2= 5760yr

R= $e^{-\lambda t}$ $e^{\lambda t}$

By taking log

$\lambda tloge=log\frac{R_0}{R}$

$\lambda t$ = log₁₀16/12 $*2.303$

$t=\frac{2.303(log4-log3)}{\lambda }$

= 2.303 (0.6020-4.771)5760/0.6931

  = 2391.20yr

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation-because more number of protons means more repulsive force which leads to instability.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- during the collision of electron and positron they form gamma radiation and these gamma particle travels in opposite direction to conserve the momentum.

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Explanation- electron cannot emit radiation while exiting because they absorbs energy in eV which is very low as compared to gamma particle . as they contain energy in MeV

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- at t=0 (dN/dt)_A= (dN/dt)_B

By drawing a perpendicular line across graph (dN/dt)_A> (dN/dt)_B so decay is faster in A than B

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Explanation- dN/dt= $\lambda N$

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Explanation- nuclei ₂He⁴ and ₁He³ have the same mass number . the element having more number of proton having more repusion so less binding energy. So ₂He⁴ have more number of proton so more repulsion so less binding energy.

This is a Long Answer Type Questions as classified in NCERT Exemplar

Explanation- B.E = (M_p+M_H-M_N)c²

B.E= (118.9058+1.0078252-119.902199)c²

B.E=0.0114362 c²

B.E= (M_p+M_H-M_N)c²

B.E= (119.902199+1.0078252-120.902822)c²

B.E= 0.0059912c²

  (ii) the existence of magic numbers indicates that the shell structure of nucleus is similar to the shell structure of an atom. This also explains peaks in binding energy curve.

This is a Long Answer Type Questions as classified in NCERT Exemplar

Explanation-