The de Broglie wavelength of a proton and \(\alpha\) -particle are equal. The ratio of their velocities is ...... .

A cylinder with adiabatic walls is closed at both ends and is divided into two compartments by a frictionless adiabatic piston. Ideal gas is filled in both (left and right) the compartments at same \(P, V, T\). Heating is started from left side until pressure changes to \(\dfrac{27P}{8}\). If initial volume of each compartment was \(9\) litres then the final volume in right-hand side compartment is __________ litres. (for this ideal gas \(C_P/C_V = 1.5\))

A satellite is launched into a circular orbit of radius \(‘R’\) around earth while a second satellite is launched into an orbit of radius \(1.02 R\). The percentage difference in the time periods of the two satellites is ......... \(\%\)

Ice at \(-20\,^oC\) is added to \(50\,g\) of water at \(40\,^oC.\) When the temperature of the mixture reaches \(0\,^oC,\) it is found that \(20\,g\) of ice is still unmelted. The amount of ice added to the water was close to ........\(g\) (Specific heat of water \(= 4.2\,J/g/^oC)\) Heat of fusion of water at \(0^oC = 334\,J/g\) )

Which of the following circuits represents a forward biased diode?


Choose the correct answer from the options given below :

If electric field intensity of a uniform plane electro magnetic wave is given as \(E =-301.6 \sin ( kz -\omega t ) \hat{a}_{ x }+452.4 \sin ( kz -\omega t )\) \(\hat{a}_{y} \frac{V}{m}\) Then, magnetic intensity \(H\) of this wave in \(Am ^{-1}\) will be [Given: Speed of light in vacuum \(c =3 \times 10^{8} ms ^{-1}\), permeability of vacuum \(\mu_{0}=4 \pi \times 10^{-7} NA ^{-2}\) ]

A string of length \(1\, m\) and mass \(5\, g\) is fixed at both ends. The tension in the string is \(8.0\, N\). The string is set into vibration using an external vibrator of frequency \(100\, Hz\). The separation between successive nodes on the string is close to .... \(cm\)

A sample contains mixture of helium and oxygen gas. The ratio of root mean square speed of helium and oxygen in the sample is _______.

A solid cylinder is released from rest from the top of an inclined plane of inclination \(30^{\circ}\) and length \(60\,cm\). If the cylinder rolls without slipping, its speed upon reaching the bottom of the inclined plane is \(...........ms ^{-1}\). (Given \(g =10\,ms ^{-2}\))

In an experiment, electrons are accelerated, from rest, by applying, a voltage of \(500 \,V.\) Calculate the radius of the path if a magnetic field \(100\,mT\) is then applied. [Charge of the electron \(= 1.6 \times 10^{-19}\,C\) Mass of the electron \(= 9.1 \times 10^{-31}\,kg\) ]

A solid ball of radius \(R\) has a charge density \(\rho \) given by \(\rho  = {\rho _0}\left( {1 - \frac{r}{R}} \right)\) for \(0 \leq r \leq R\). The electric field outside the ball is

A metal bal of mass \(0.1\, kg\) is heated upto \(500\,{}^oC\) and dropped into a vessel of heat capacity \(800\, JK^{-1}\) and containing \(0.5\, kg\) water. The initial temperature of water and vessel is \(30\,{}^oC\). ........ \(\%\) is the approximate percentage increment in the temperature of the water. [Specific heat Capacities of water and metal are, respectively \(4200\, Jkg^{-1}K^{-1}\) and \(400\, Jkg^{-1}K^{-1}\)]

A paramagnetic substance in the form of a cube with sides \(1\, cm\) has a magnetic dipole moment of \(20 \times 10^{-6}\, J/T\) when a magnetic intensity of \(60 \times 10^3\, A/m\) is applied. Its magnetic susceptibility is