$A$ Carnot engine,having an efficiency of $\eta = 1/10$ as a heat engine,is used as a refrigerator. If the work done on the system is $10 \ J$,the amount of energy absorbed from the reservoir at a lower temperature is .......... $J$.

Identify the major product formed when $2-$Methylhexan$-3-$ol is heated with concentrated sulphuric acid.

For the reaction $2NO_2 + F_2 \to 2NO_2F$,the following mechanism has been provided:
$NO_2 + F_2 \xrightarrow{slow} NO_2F + F$
$NO_2 + F \xrightarrow{fast} NO_2F$
Thus,the rate expression of the above reaction can be written as:

Let $R_1$ be a relation defined by $R_1 = \{(a, b) | a \geq b, a, b \in \mathbb{R}\}$. Then $R_1$ is

$A$ telescope has an objective lens of focal length $144\, cm$ and an eyepiece of focal length $6\, cm$. Find the magnifying power of the telescope for normal adjustment.

$A$ charged particle with charge $q$ and mass $m$ starts with an initial kinetic energy $K$ at the centre of a uniformly charged spherical region of total charge $Q$ and radius $R$. Charges $q$ and $Q$ have opposite signs. The spherically charged region is not free to move and kinetic energy $K$ is just sufficient for the charged particle to reach the boundary of the spherical charge. How much time does it take the particle to reach the boundary of the region?