The figure shows a plot of binding energy per nucleon $E_b$ against the nuclear mass $M$. $A, B, C, D, E, F$ correspond to different nuclei. Consider four reactions:
$(i)$ $A + B \to C + \varepsilon$
$(ii)$ $C \to A + B + \varepsilon$
$(iii)$ $D + E \to F + \varepsilon$
$(iv)$ $F \to D + E + \varepsilon$
where $\varepsilon$ is the energy released. In which reactions is $\varepsilon$ positive?

$A$ transition metal $M$ forms a volatile chloride with a vapor density of $94.8$. If it contains $74.75\%$ chlorine,what is the formula of the metal chloride?

In dicot stem,vascular bundles are

$A$ car $P$ approaching a crossing at a speed of $10\, m/s$ sounds a horn of frequency $700\, Hz$ when $40\, m$ in front of the crossing. The speed of sound in air is $340\, m/s$. Another car $Q$ is at rest on a road which is perpendicular to the road on which car $P$ is reaching the crossing (see figure). The driver of car $Q$ hears the sound of the horn of car $P$ when he is $30\, m$ in front of the crossing. The apparent frequency heard by the driver of car $Q$ is .... $Hz$.

If a polygon of $n$ sides has $275$ diagonals,then $n$ is equal to

From the origin,chords are drawn to the circle $(x - 1)^2 + y^2 = 1$. The equation of the locus of the midpoints of these chords is: