Which of the following facilitates the opening of the stomatal aperture?

The magnetic flux through a stationary loop with resistance $R$ varies during an interval of time $T$ as $\phi = a t(T - t)$. The heat generated during this time,neglecting the inductance of the loop,will be:

The concept of chemical evolution is based on

An iron load of $2 \ kg$ is suspended in air from the free end of a sonometer wire of length $1 \ m$. $A$ tuning fork of frequency $256 \ Hz$ is in resonance with $\frac{1}{\sqrt{7}}$ times the length of the sonometer wire. If the load is immersed in water,the length of the wire in metres that will be in resonance with the same tuning fork is (Specific gravity of iron $= 8$)

$_6 C^{12}$ and $_1 T^3$ are formed in nature due to the nuclear reaction of a neutron with:

The equation of the pair of lines joining the origin to the points of intersection of $x^2+y^2=9$ and $x+y=3$ is: