Assertion:  It is not possible to use  ³⁵Cl  as  the fuel for fusion energy.

Reason: The binding energy of  ³⁵Cl is too small.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion: The number of electrons in a p-type silicon  semiconductor is less than the number of electrons in a pure silicon semiconductor at room temperature.

Reason: It is due to law of mass action.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

A nucleus of mass number A, originally at rest, emits on  $\mathrm{\alpha }$-particle with speed v. The daughter nucleus recoil with speed a speed 

• $\frac{2\mathrm{v}}{\mathrm{A} + 4}$

• $\frac{4\mathrm{v}}{\mathrm{A} + 4}$

• $\frac{4\mathrm{v}}{\mathrm{A} - 4}$

• $\frac{2\mathrm{v}}{\mathrm{A} - 4}$

When an electron-positron pair annihilates, the energy released is about

• 0.8 × 10^-13 J

• 1.6 × 10^-13 J

• 3.2 × 10^-13 J

• 4.8 × 10^-13 J

Two parallel beams of positrons moving in the same direction will

• repel each other

• will not interact with each other

• attract each other

• be deflected normal to the plane containing the two beams

256.

Carbon dating is best suited for determining the age of fossils if their age in years is of the order of

• 10⁸

• 10⁴

• 10⁴

• 10⁶

The dependence of binding energy per nucleon, B_A  on the mass number A, is represented by

Assertion:  ⁹⁰Sr from the radioactive fall out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of the production of red blood cells.

Reason: The energies β-particles emitted in the decay of ⁹⁰Sr damage the bone marrow.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are but reason is not the correct explanation of assertion  

• If asserion and reason is false

• If both assertion and reason are false

Assertion: Energy is released in nuclear fission.

Reason: Total binding energy of the fission fragments is larger than the total binding energy of the parent nucleus.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason is false

Assertion:  Heavy water preferred ever ordinary water as a moderator in reactors. 

Reason:  Heavy water, used for slowing down the neutrons, has lesser absorption probability
of neutrons than ordinary water.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false