For $x \in \mathbb{R}$,the range of $3 \cos (4x - 5) + 4$ lies in the interval

Which among the following is $NOT$ a feature of $S_N2$ mechanism?

Heat is supplied to a diatomic gas at constant pressure. The ratio of $\Delta Q : \Delta U : \Delta W$ is

$5.6 \, \text{liter}$ of helium gas at $STP$ is adiabatically compressed to $0.7 \, \text{liter}$. Taking the initial temperature to be $T_1$,the work done in the process is

In an entrance test,there are multiple-choice questions. There are four possible answers to each question,of which one is correct. The probability that a student knows the answer to a question is $90\%$. If he gets the correct answer to a question,then the probability that he was guessing is:

The number of $5$-digit numbers that are not divisible by $5$ and consist of different odd digits is: