Atoms and Nucle...

Assertion Cobalr-60 is useful in cancer therapy.
Reason Cobalt - 60 is source of γ-radiations capable of killing cancerous cell.

Assertion Amongst alpha, beta and gamma rays, α - particle has maximum penetrating power.
Reason The alpha particle is heavier than beta and gamma rays.

Assertion The ionising power of β-particle is less compared to α-particles but their penetrating power is more.
Reason The mass of β-particle is less than the mass of α-particle.

Assertion The mass of β-particles when they are emitted is higher than the mass of electrons obtained by other means.
Reason β-particle and electron,both are similar particles.

Assertion It is not possible to use ³⁵Cl as the fuel for fusion energy.
ReasonThe binding energy of ³⁵Cl is too small.

Assertion Neutrons penetrate matter more readily as compared to protons.
Reason Neutrons are slightly more massive than protrons

Assertion Bohr had to postulate that the electrons in stationary orbits around the nucleus do not radiate.
Reason According to classical physics all moving electrons radiate

Assertion Density of all the nuclei is same.
Reason Radius of nucleus is directly proportional to the cube root of mass number.

Assertion Isobars are the element having same mass number but different atomic number.
Reason Neutrons and protons are present inside nucleus.

Assertion According to classical theory, the proposed path of an electron in Rutherford atom model will be parabolic
Reason According to electromagnetic theory an accelerated particle continuously emits radiation