Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Joining of light nuclei of elements to form a heavy nucleus with the release of energy is called:

Assertion  :   Annihilation of electron and positron is an example of decay of charges.
Reason      : In the process of annihilation an electron and a positron combine to give a gamma particle.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If assertion is false but reason is true.

The ratio between Bohr radii is:

The rate of change of current needed to induce an emf of 8V in 0.1H coil is.

A particle of mass m and charge q moves with a constant velocity v along the positive x direction. It enters a region containing a uniform magnetic field B directed along the negative z direction, extending from  x = a to x = b. The minimum value of v required so that the particle can just enter the region x > b  is(a) qb B/m(b) q(b – a) B/m(c) qaB/m(d) q(b + a)B/2m

Nuclear binding energy is equivalent to(a) Mass of proton(b) Mass of neutron(c) Mass of nucleus(d) Mass defect of nucleus

A shortsighted person uses for clear vision :

Unit of radioactivity is Rutherford. Its value is

Which of the following are electromagnetic waves?

Thin films like soap bubbles and oil floating on water can create colorful patterns. Which of the following explanations most accurately describes why this happens?