Data Entry - Physics

If the lines $3x + 4y - 14 = 0$ and $6x + 8y + 7 = 0$ are both tangents to a circle,then its radius is

Which of the following pairs of organs includes only the endocrine glands?

Among the following series of transition metal ions,the one where all metal ions have $3d^2$ electronic configuration is

$A$ steady current flows in a long wire. It is bent into a circular loop of one turn and the magnetic field at the centre of the coil is $B$. If the same wire is bent into a circular loop of $n$ turns,the magnetic field at the centre of the coil is

Which of the following is correctly matched?