The wavelength of a $1 \ keV$ photon is $1.24 \times 10^{-9} \ m$. What is the frequency of a $1 \ MeV$ photon?

Given below are two statements:-
Statement-$I$: Morphine is a narcotic analgesic. It helps in relieving pain without producing sleep.
Statement-$II$: Morphine and its derivatives are obtained from opium poppy.
In the light of the above statements,choose the correct answer from the options given below.

If the pair of straight lines $xy-x-y+1=0$ and the line $ax+2y-3a=0$ are concurrent,then $a$ is equal to

The resistance of an ammeter is $13 \Omega$ and its scale is graduated for a current up to $100 \text{ A}$. After an additional shunt has been connected to this ammeter,it becomes possible to measure currents up to $750 \text{ A}$ by this meter. The value of the shunt resistance is

Which of the following is the correct order of acidic strength?

Two rigid boxes containing different ideal gases are placed on a table. Box $A$ contains one mole of nitrogen at temperature $T_0$,while box $B$ contains one mole of helium at temperature $(7/3) T_0$. The boxes are then put into thermal contact with each other,and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of the boxes). The final temperature of the gases $T_f$ in terms of $T_0$ is: