Which of the following is an oilseed crop?

$A$ light ray of wavelength $\lambda$ is passing through a pinhole of diameter $D$ and the effect is observed on a screen placed at a distance $L$ from the pinhole. The approximations of geometrical optics are applicable,if

Which of the following is considered an acellular organism?

When zeolite (hydrated sodium aluminium silicate) is treated with hard water,the sodium ions are exchanged with:

$A$ 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

Which of the following is the strongest $o-p$ directing group?