Activity of a radioactive sample decreases to \(\frac{1}{3}\)^rd of its original value in \(3\) days. Then, in \(9\) days its activity will become:

1.	\(\frac{1}{27}\) of the original value
2.	\(\frac{1}{9}\) of the original value
3.	\(\frac{1}{18}\) of the original value
4.	\(\frac{1}{3}\) of the original value

A tuning fork A produces \(4\) beats/s with another tuning fork B of frequency \(320\) Hz. On filing one of the prongs of A, \(4\) beats are again heard when sounded with the same fork B. Then, the frequency of fork A before filing is:
1. \(328\) Hz
2. \(316\) Hz
3. \(324\) Hz
4. \(320\) Hz

If there were no gravity, which of the following would not be there for a fluid?
1. Viscosity
2. Surface tension
3. Pressure
4. Archimedes upward thrust

A choke is preferred to resistance for limiting current in AC circuit because:

The velocity-time curve for a body projected vertically upwards is:
1. parabola
2. ellipse
3. hyperbola
4. straight line

If \(r_1\) and \(r_2\) are the radii of the atomic nuclei of mass numbers \(64\) and \(125\) respectively, then the ratio \(\frac{r_1}{r_2}\) is:
1. \(\frac{64}{125}\)
2. \(\sqrt{\frac{64}{125}}\)
3. \(\frac54\)
4. \(\frac45\)

The ionization energy of \(\mathrm{Li^{2+}}\) is equal to:
1. \(9hcR \)
2. \(6hcR\)
3. \(2hcR\)
4. \(hcR\)

A current of \(5\) A is passing through a metallic wire of cross-sectional area \(4\times10^{-6}\) m². If the density of charge carriers of the wire is \(5\times10^{26}\) m^-3, then the drift velocity of the electrons will be:
1. \(1\times 10^2\) m/s
2. \(1.56 \times10^{-2}\) m/s
3. \(1.56 \times10^{-3}\) m/s
4. \(1\times 10^{-2}\) m/s

The numerical ratio of displacement to the distance covered is always:

The principle of LASER action involves: