When two related populations occupy geographically or spatially separate areas,they are called

The figure shows wave fronts in still water,moving in the direction of the arrow towards the interface $PQ$ between a shallow region and a deep (denser) region. Which of the lines shown may represent one of the wave fronts in the deep region?

Which one of the following conditions is incorrect for a well-behaved wave function $(\psi)$?

Select the correct statement from the following.

$A$ galvanometer,having a resistance of $50 \Omega$,gives a full-scale deflection for a current of $0.05 \text{ A}$. The length in metres of a resistance wire of cross-sectional area $2.97 \times 10^{-2} \text{ cm}^2$ that can be used to convert the galvanometer into an ammeter which can read a maximum of $5 \text{ A}$ current is: (Specific resistance of the wire $= 5 \times 10^{-7} \Omega\text{-m}$)

Which of the following is $NOT$ obtained when a mixture of methyl bromide and ethyl bromide is treated with sodium metal in the presence of dry ether?