In the circuit, shown the galvanometer $$G$$ of resistance $$60 \Omega$$ is shunted by a resistance $$r=0.02 \Omega$$. The current through $$R$$ is nearly $$1 \mathrm{~A}$$. The value of resistance $$R$$ (in ohm) is nearly
In a circuit $$L, C$$ and $$R$$ are connected in series with an alternating voltage source of frequency $$f$$. The current leads the voltage by $$45^{\circ}$$. The value of $$C$$ is
The graph between the energy log E of an electron and its de-Broglie wavelength log $$\lambda$$ will be
The half-life of a radioactive substance is $$20 \mathrm{~min}$$. The approximate time interval $$\left(t_2-t_1\right)$$ between the time $$t_2$$, when $$\frac{2}{3}$$ of it has decayed and time $$t_1$$ when $$\frac{1}{3}$$ of it had decayed is