The transition from the state $n = 3$ to $n = 1$ in a hydrogen-like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from

If $n$ is an integer with $0 \leq n \leq 11$,then the minimum value of $n!(11-n)!$ is attained when a value of $n$ equals to

$A$ rifle of $20 ~kg$ mass can fire $4$ bullets per second. The mass of each bullet is $35 \times 10^{-3} ~kg$ and its final velocity is $400 ~ms^{-1}$. What force must be applied on the rifle so that it does not move backwards while firing the bullets (in $~N$)?

Which of the following lubricates ligaments or tendons and is an important constituent of synovial fluid of bones?

At $550 \ K$,the $K_c$ for the following reaction is $10^4 \ L \ mol^{-1}$: $X_{(g)} + Y_{(g)} \rightleftharpoons Z_{(g)}$. At equilibrium,it was observed that $[X] = \frac{1}{2}[Y] = \frac{1}{2}[Z]$. What is the value of $[Z]$ (in $mol \ L^{-1}$) at equilibrium?

How many geometrical isomers are possible for the compound shown below?