Which of the following is characterized by a cell wall made of peptidoglycan?

$A$ convex lens is made up of three different materials as shown in the figure. For a point object placed on its axis,the number of images formed are

Which of the following is not a colligative property?

If $x$ is small,so that $x^2$ and higher powers can be neglected,then the approximate value for $\frac{(1-2 x)^{-1}(1-3 x)^{-2}}{(1-4 x)^{-3}}$ is

$A$ body is executing simple harmonic motion. At a displacement $x$ its potential energy is $E_1$ and at a displacement $y$ its potential energy is $E_2$. The potential energy $(E)$ at displacement $(x+y)$ is

The sum of $n$ terms of the series $1^3+3^3+5^3+7^3+\ldots$ is