An ideal gas expands adiabatically. $$(\gamma=1 \cdot 5)$$ To reduce the r.m.s. velocity of the molecules 3 times, the gas has to be expanded
A metal surface of work function $$1 \cdot 13 \mathrm{~eV}$$ is irradiated with light of wavelength $$310 \mathrm{~nm}$$. The retarding potential required to stop the escape of photoelectrons is [Take $$\frac{\mathrm{hc}}{\mathrm{e}}=1240 \times 10^{-9} \mathrm{SI}$$ units]
Two cars A and B start from a point at the same time in a straight line and their positions are represented by $$\mathrm{R}_{\mathrm{A}}(\mathrm{t})=$$ at $$+\mathrm{bt}^2$$ and $$\mathrm{R}_{\mathrm{B}}(\mathrm{t})=x \mathrm{t}-\mathrm{t}^2$$. At what time do the cars have same velocity?
The a.c. source of e.m.f. with instantaneous value '$$e$$' is given by $$e=200 \sin (50 t)$$ volt. The r.m.s. value of current in a circuit of resistance $$50 \Omega$$ is