An electron revolving in \(\mathrm{n}^{\text {th }}\) Bohr orbit has magnetic moment \(\mu_n\). If \(\mu_n\) \(\alpha\) \(n^x\), the value of \(x\) is _______.

\(A, B, C\) and \(D\) are four different physical quantities having different dimensions. None of them is dimensionless. But we know that the equation \(AD = C\, ln\, (BD)\) holds true. Then which of the combination is not a meaningful quantity ?

An ideal monoatomic gas is confined in a cylinder by a spring loaded piston of cross section \(8.0\times10^{-3}\, m^2\) . Initially the gas is at \(300\, K\) and occupies a volume of \(2.4\times10^{-3}\, m^3\) and the spring is in its relaxed state as shown in figure. The gas is heated by a small heater until the piston moves out slowly by \(0.1\, m\). The force constant of the spring is \(8000\, N/m\) and the atmospheric pressure is \(1.0\times10^5\, N/m^2\) . The cylinder and the piston are thermally insulated. The piston and the spring are massless and there is no friction between the piston and the cylinder. The final temperature of the gas will be: (Neglect the heat loss through the lead wires of the heater . The heat capacity of the heater coil is also negligible)

A small bob tied at one end of a thin string of length \(1\, m\) is describing a vertical circle so that the maximum and minimum tension in the string are in the ratio \(5: 1 .\) The velocity of the bob at the height position is ............. \(m / s\) (Take \(\left.g=10 \,m / s ^{2}\right)\)

Paramagnetic substances: \(A\). align themselves along the directions of external magnetic field. \(B\). attract strongly towards external magnetic field. \(C\). has susceptibility little more than zero. \(D\). move from a region of strong magnetic field to weak magnetic field. Choose the most appropriate answer from the options given below:

Two point charges \(q_1\,(\sqrt {10}\,\,\mu C)\) and \(q_2\,(-25\,\,\mu C)\) are placed on the \(x-\) axis at \(x = 1\,m\) and \(x = 4\,m\) respectively. The electric field (in \(V/m\) ) at a point \(y = 3\,m\) on \(y-\) axis is, [ take \({\mkern 1mu} {\mkern 1mu} \frac{1}{{4\pi {\varepsilon _0}}} = 9 \times {10^9}{\mkern 1mu} {\mkern 1mu} N{m^2}{C^{ - 2}}{\rm{ }}\) ]

In the given figure an ammeter \(A\) consists of a \(240 \Omega\) coil connected in parallel to a \(10 \Omega\) shunt. The reading of the ammeter is _______ \(\mathrm{mA}\).

A positive point charge is released from rest at a distance \(r_0\) from a positive line charge with uniform density. The speed \((v)\) of the point charge, as a function of instantaneous distance \(r\) from line charge, is proportional to

If the function \(f(x)=\frac{\cos (\sin x)-\cos x}{x^{4}}\) is continuous at each point in its domain and \(f (0)=\frac{1}{ k },\) then \(k\) is ........

A body of mass 14 kg initially at rest explodes and breaks into three fragments of masses in the ratio \(2:2:3\). The two pieces of equal masses fly off perpendicular to each other with a speed of \(18~m/s\) each. The velocity of the heavier fragment is ___________ \(m/s\).

Let \(A=\{1,2,3, \ldots 20\}\). Let \(R_1\) and \(R_2\) two relation on \(\mathrm{A}\) such that \(\mathrm{R}_1=\{(\mathrm{a}, \mathrm{b}): \mathrm{b}\) is divisible by \(\mathrm{a}\}\) \(\mathrm{R}_2=\{(\mathrm{a}, \mathrm{b}): \mathrm{a}\) is an integral multiple of \(\mathrm{b}\}\). Then, number of elements in \(R_1-R_2\) is equal to ...........

A capacitor of capacitance \(\mathrm{C}\) and potential \(\mathrm{V}\) has energy \(E\). It is connected to another capacitor of capacitance \(2 \mathrm{C}\) and potential \(2 \mathrm{~V}\). Then the loss of energy is \(\frac{x}{3} E\), where \(\mathrm{x}\) is _______.

The differential equation satisfied by the system of parabolas \(y ^{2}=4 a ( x + a )\) is