The shield-shaped cotyledon seen in monocot seeds is known as:

When a certain metallic surface is illuminated with monochromatic light of wavelength $\lambda$,the stopping potential for photoelectric current is $3V_0$. When the same surface is illuminated with light of wavelength $2\lambda$,the stopping potential is $V_0$. The threshold wavelength of this surface for the photoelectric effect is:

Energy of an electron in the ground state of the hydrogen atom is $-2.18 \times 10^{-18} \, J$. Calculate the ionization enthalpy of atomic hydrogen in terms of $J \, mol^{-1}$.

Inbreeding is carried out in animal husbandry because it

Laughing gas is prepared by heating

An object is placed at a distance of $50 \, cm$ in front of a convex mirror. $A$ plane mirror is inserted covering half of the convex mirror. If the distance between the object and the plane mirror is $30 \, cm$,it is observed that there is no parallax between the images formed by the two mirrors. The radius of curvature of the convex mirror is ..... $cm$.