If the equations $x^2+ax+b=0$ and $x^2+bx+a=0$ $(a \neq b)$ have a common root,then $a+b$ is equal to

In an $A.C.$ circuit,$V$ and $I$ are given by $V = 100 \sin(100t) \ V$ and $I = 100 \sin(100t + \frac{\pi}{3}) \ mA$. The power dissipated in the circuit is ...... $W$.

$A$ ball $A$ of mass $m$ moving along the positive $x$-direction with kinetic energy $K$ and momentum $p$ undergoes an elastic head-on collision with a stationary ball $B$ of mass $M$. After the collision,ball $A$ moves along the negative $x$-direction with kinetic energy $K/9$. The final momentum of ball $B$ is:

What is the final product $(B)$ of this sequence?

The compound,found in nature in gas phase but ionic in solid state is

Match the following (Take the relative strength of the strongest fundamental forces in nature as $1$):
| List-$I$ (Fundamental forces in nature) | List-$II$ (Relative strength) |
| :--- | :--- |
| $(A)$ Strong nuclear force | $(e)$ $10^{-2}$ |
| $(B)$ Weak nuclear force | $(f)$ $1$ |
| $(C)$ Electromagnetic force | $(g)$ $10^{10}$ |
| $(D)$ Gravitational force | $(h)$ $10^{-13}$ |
| | $(i)$ $10^{-39}$ |
The correct match is: