$A$ wire fixed at the upper end stretches by length $l$ by applying a force $F$. The work done in stretching is

Which one of the following is the correct order of the second ionisation potential of $Na, Ne, Mg$ and $Al$?

Which one of the following statements is incorrect?

Let $f(x)$ be defined for all $x > 0$ and be continuous. Let $f(x)$ satisfy $f(\frac{x}{y}) = f(x) - f(y)$ for all $x, y > 0$ and $f(e) = 1$. Then:

What is the maximum value of the force $F$ such that the block shown in the arrangement does not move (in $N$)? (Take $g = 10 \ m/s^2$)

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: