Two satellites $A$ and $B$,having a ratio of masses $3 : 1$,are in circular orbits of radii $r$ and $4r$ respectively. Calculate the ratio of the total mechanical energy of $A$ and $B$.

Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids,the main reason being

Which of the following has the lowest boiling point?

Match the points on the curve $2y^2 = x + 1$ with the slopes of the normals at those points and choose the correct answer.

Point	Slope of the normal
$A. (7, 2)$	$1. -4\sqrt{2}$
$B. (0, 1/\sqrt{2})$	$2. -8$
$C. (1, -1)$	$3. 4$
$D. (3, \sqrt{2})$	$4. 0$
	$5. -2\sqrt{2}$

An infinite number of electric charges each equal to $5 \text{ nC}$ (magnitude) are placed along the $X$-axis at $x=1 \text{ cm}, x=2 \text{ cm}, x=4 \text{ cm}, x=8 \text{ cm} \dots$ and so on. In this setup, if the consecutive charges have opposite signs, then the electric field in $\text{N/C}$ at $x=0$ is: $\left(\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9 \text{ N} \cdot \text{m}^2/\text{C}^2\right)$

If the bond length and dipole moment of a diatomic molecule are $1.25 \ \mathring{A}$ and $1.0 \ D$ respectively,what is the per cent ionic character of the bond?