A liquid does not wet the solid surface if the angle of contact is:
1. equal to $\mathrm{}$\(45^{\circ}\)
2. equal to \(60^{\circ}\)$\mathrm{}$
3. greater then \(90^{\circ}\)$\mathrm{}$
4. zero 

A point mass \(m\) is moved in a vertical circle of radius \(r\) with the help of a string. The velocity of the mass is \(\sqrt{7gr} \) at the lowest point. The tension in the string at the lowest point is:

An object is placed on the principal axis of a concave mirror at a distance of \(1.5f\) (\(f\) is the focal length). The image will be at:

The half-life of a radioactive sample undergoing \(\alpha- \text{decay}\) is $1.4\times {10}^{17}$ $\sec$. If the number of nuclei in the sample is $2.0$ $\times$ ${10}^{21}$, the activity of the sample is nearly equal to:

1.  ${10}^4$ $Bq$

2.  ${10}^5$ $Bq$

3.  ${10}^6$ $Bq$

4.  ${10}^3$ $Bq$

If the critical angle for total internal reflection from a medium to vacuum is \(45^{\circ}\), the velocity of light in the medium is: 

A wheel with \(20\) metallic spokes, each \(1\) m long, is rotated with a speed of \(120\) rpm in a plane perpendicular to a magnetic field of \(0.4~\text{G}\). The induced emf between the axle and rim of the wheel will be:
\((1~\text{G}=10^{-4}~\text{T})\)
1. \(2.51 \times10^{-4}\) V
2. \(2.51 \times10^{-5}\) V
3. \(4.0 \times10^{-5}\) V
4. \(2.51\) V

Which of the following gate is called the universal gate? 
1. \(\mathrm{OR}\) gate 
2. \(\mathrm{AND}\) gate 
3. \(\mathrm{NAND}\) gate 
4. \(\mathrm{NOT}\) gate 

The \((P\text{-}V)\) diagram for an ideal gas in a piston-cylinder assembly undergoing a thermodynamic process is shown in the figure. The process is: