$$\mathrm{K}_1$$ and $$\mathrm{K}_2$$ are maximum kinetic energies of photoelectrons emitted when lights of wavelength $$\lambda_1$$ and $$\lambda_2$$ respectively are incident on a metallic surface. If $$\lambda_1=3 \lambda_2$$, then
An object of mass $$3 \mathrm{~kg}$$ moves due to an applied constant force such that its position along $$\mathrm{X}$$ axis is given by $$x=\frac{t^3}{3}$$ where $$x$$ is in meters and $t$ in seconds. The work done in 1 second is
The radius of a nucleus as measured by electron scattering is $$4.8 \mathrm{~fm}$$. The mass number of nucleus is most likely to be
Light enters at an angle of incidence in a transparent rod of refractive index '$$n$$'. The least value of '$$n$$' for which the light once entered into it will not leave it through its lateral face whatsoever be the value of the angle of incidence is