A metallic rod of mass per unit length $$0.5 \mathrm{~kg} \mathrm{~m}^{-1}$$ is lying horizontally on a smooth inclined plane which makes an angle of $$30^{\circ}$$ with the horizontal. A magnetic field of strength $$0.25 \mathrm{~T}$$ is acting on it in the vertical direction. When a current $$I$$ is flowing through it, the rod is not allowed to slide down. The quantity of current required to keep the rod stationary is
A nuclear reactor delivers a power of $$10^9 \mathrm{~W}$$, the amount of fuel consumed by the reactor in one hour is
The displacement $$x$$ (in $$\mathrm{m}$$) of a particle of mass $$m$$ (in $$\mathrm{kg}$$) moving in one dimension under the action of a force, is related to time $$t$$ (in sec) by $$t=\sqrt{x}+3$$. The displacement of the particle when its velocity is zero, will be
Two objects are projected at an angle $$\theta^{\circ}$$ and $$\left(90-\theta^{\circ}\right)$$, to the horizontal with the same speed. The ratio of their maximum vertical heights is