Which of the following plant groups possesses spores and embryos but is seedless and lacks vascular tissues?

The ratio of anion radius to cation radius of a crystal is $10: 9.3$. Then,the coordination number of the cation in the crystal is

If the normal to the curve $y^2 = 5x - 1$ at the point $(1, -2)$ is of the form $ax - 5y + b = 0$,then $a$ and $b$ are:

Two circular coils can be arranged in any of the three situations shown in the figure. Their mutual inductance will be

Which of the following options is correct for an object having a straight-line motion represented by the following graph?

$A$ coil having $N$ turns is wound tightly in the form of a spiral with inner and outer radii $a$ and $b$ respectively. When a current $I$ passes through the coil,the magnetic field at the centre is