Ectophloic siphonostele is found in

$A$ proton (mass $m$ and charge $+e$) and an $\alpha$-particle (mass $4m$ and charge $+2e$) are projected with the same kinetic energy at right angles to a uniform magnetic field. Which one of the following statements is true?

In a $\triangle ABC$,the expression $\frac{(a+b+c)(b+c-a)(c+a-b)(a+b-c)}{4b^2c^2}$ is equal to:

Three bulbs of $40\, W$,$60\, W$,and $100\, W$ are connected in series to a $220\, V$ supply. Which bulb has the minimum resistance?

The vector $c \cdot (b+c) \times (a+b+c)$ is equal to

Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of: