Assertion (A) At critical temperature, surface tension of liquids become zero.
Reason (R) At critical temperature, intermolecular forces for liquids and gases become equal.

A proton when accelerated through a potential difference of \(V\), has a de-Broglie wavelength \(\lambda\) associated with it. If an \(\alpha\)-particle is to have the same de-Broglie wavelength \(\lambda\), it must be accelerated through a potential difference of

The amplitude of a damped harmonic oscilator becomes \(50 \%\) of its initial value in a time of 12 s. If the amplitude of the oscillator at a time of 36 s is \(\mathrm{x} \%\) of its initial amplitude, then the value of \(x\) is

A wire is stretched 1 mm by a force \(F\). If a second wire of same material, same length and 4 times the diameter of the first wire is stretched by the same force \(F\), then the elongation of the second wire is

Match the following List I with List II.
\(\begin{array}{|c|c|c|}
\hline & \text { List I } & \text { List II } \\
\hline \text { (A) } & \text { Transverse wave (i) } & \begin{array}{l}
\text {Vibrations parallel to the } \\
\text {direction of propagation }
\end{array} \\
\hline \text { (B) } & \begin{array}{l}
\text {Longitudinal wave }
\end{array} & \begin{array}{l}
\text {Vibrations perpendicular to } \\
\text {the direction of propagation }
\end{array} \\
\hline \text { (C) } & \text { Beats } & \begin{array}{l}
\text {Superposition of waves } \\
\text {travelling in the opposite directions }
\end{array} \\
\hline \text { (D) } & \text { Stationary waves (iv) } & \begin{array}{l}
\text {Superposition of waves } \\
\text {travelling in same direction }
\end{array} \\
\hline
\end{array}\)
The correct answer is

The law which states that 'a variation in an electric field causes magnetic field', is

The length and area of cross-section of a copper wire are respectively 30 m and \(6 \times 10^{-7} \mathrm{~m}^2\). If the resistivity of copper is \(1.7 \times 10^{-8} \Omega \mathrm{~m}\), then the resistance of the wire is

The bob of simple pendulum is hanging vertically down from a fixed identical bob by means of a sting of length \(l\). If both bobs are charged with a charge \(q\) each, time period of the pendulum is : (ignore the radii of the bobs)

The system \(x+2 y+3 z=4,4 x+5 y+3 z=5,3 x+4 y+3 z=\lambda\) is consistent and \(3 \lambda=n+100\), then \(n=\)

If the function \(f(x)=a x^3+b x^2+26 x-24\) satisfies the conditions of Rolle's theorem in \([2,4]\) and \(f^{\prime}\left(3+\frac{1}{\sqrt{3}}\right)=0\), then the value of \(a b\) is equal to

At \(550 \mathrm{~K}\), the \(K_c\) for the following reaction is \(10^4 \mathrm{~mol}^{-1} \mathrm{~L} X(g)+Y(g) \rightleftharpoons Z(g)\)

At equilibrium, it was observed that \([X]=\frac{1}{2}[Y]=\frac{1}{2}[Z]\)

What is the value of [Z] (in \(\mathrm{mol} \mathrm{L}^{-1}\) ) at equilibrium?

In an examination, a student has to write exams in 8 different subjects. He is declared fail if he fails in at least one subject. The number of ways in which he can fail is

$A(2,3,4), B(4,5,7), C(2,-6,3), D(4,-4, k)$ are four points. If the line $\overline{AB}$ is parallel to $\overline{CD}$ then $k$ is equal to