Two ions of masses $4 \ amu$ and $16 \ amu$ have charges $+2 e$ and $+3 e$ respectively. These ions pass through a region of constant perpendicular magnetic field. If the kinetic energy of both ions is the same,then:

Choose the incorrect statement from the following:
$S1:$ The efficiency of a heat engine can be $1$,but the coefficient of performance of a refrigerator can never be infinity.
$S2:$ The first law of thermodynamics is basically the principle of conservation of energy.
$S3:$ The second law of thermodynamics does not allow several phenomena consistent with the first law.
$S4:$ $A$ process,whose only result is to transfer heat from a colder to a hotter object,is impossible.

In a cyclic process,the work done by the system is

The angle between the pair of straight lines formed by joining the points of intersection of $x^2+y^2=4$ and $y=3x+c$ to the origin is a right angle. Then $c^2$ is equal to

Soil erosion can be prevented by

Jumping genes are found in: