A proton, an electron, and a Helium nucleus, have the same energy. They are in circular orbitals in a plane due to magnetic field perpendicular to the plane. Let \(r_p, r_e\) and \(r_{He}\) be their respective radii, then

In the figure shown \(ABC\) is a uniform wire . If centre of mass of wire lies vertically below point \(A\) , then \(\frac{{BC}}{{AB}}\) is close to 

Magnetic field in a plane electromagnetic wave is given by  \(\vec B = {B_0}\,\sin \,\left( {kx + \omega t} \right)\hat jT\)  Expression for corresponding electric field will be Where \(c\) is speed of light

Given below are two statements : one is labelled as Assertion \(A\) and the other is labelled as Reason \(R\). Assertion \(A\) : When a body is projected at an angle \(45^{\circ}\), it's range is maximum. Reason \(R\) : For maximum range, the value of \(\sin 2 \theta\) should be equal to one. In the light of the above statements, choose the correct answer from the options given below :

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency \(10\ GHz\). What is the frequency of the microwave measured by the observer?.......\(GHz\) ( speed of light \(= 3 \times  10^8 \) \(ms^{-1}\))

A system of two blocks of masses \(m =2 \; kg\) and \(M=8 \; kg\) is placed on a smooth table as shown in figure. The coefficient of static friction between two blocks is \(0.5\). The maximum horizontal force \(F\) that can be applied to the block of mass \(M\) so that the blocks move together will be \(\dots \; N\)

A copper rod of mass \(m\) slides under gravity on two smooth parallel rails, with separation \(l\) and set at an angle of \(\theta\) with the horizontal. At the bottom, rails are joined by a resistance \(R\). There is a uniform magnetic field \(B\) normal to the plane of the rails, as shown in the figure. The terminal speed of the copper rod is

Two discs of moment of inertia \(I_1=4 \mathrm{~kg} \mathrm{~m}^2\) and \(\mathrm{I}_2=2 \mathrm{~kg} \mathrm{~m}^2\) about their central axes & normal to their planes, rotating with angular speeds \(10 \mathrm\ {rad} / \mathrm{s}\) & \(4  \mathrm\ {rad} / \mathrm{s}\) respectively are brought into contact face to face with their axe of rotation coincident. The loss in kinetic energy of the system in the process is _______ \(\mathrm{J}\).

The displacement current of \(4.425 \,\mu A\) is developed in the space between the plates of parallel plate capacitor when voltage is changing at a rate of \(10^{6} \,Vs ^{-1}\). The area of each plate of the capacitor is \(40 \,cm ^{2}\). The distance between each plate of the capacitor is \(x \times 10^{-3} \,m\). The value of \(x\) is ................ (Permittivity of free space, \(\varepsilon _{0}=8.85 \times 10^{-12} \,C ^{2} N ^{-1} m ^{-2}\) )

A body of mass \(0.5\, kg\) travels on straight line path with velocity \(v =\left(3 x ^{2}+4\right) m / s\). The net workdone by the force during its displacement from \(x =0\) to \(x =2\, m\) is\(.......J\)

Given that \(1\,g\) of water in liquid phase has volume \(1\,cm^3\) and in vapour phase \(1671\, cm^3\) at atmospheric pressure and the latent heat of vaporization of water is \(2256\,J/g;\) the change in the internal energy in joules for \(1\,g\) of water at \(373\,K\) when it changes from liquid phase to vapour phase at the same temperature is ....... \(J\)

In the figure shown below, a resistance of \(150.4 \Omega\) is connected in series to an ammeter A of resistance \(240 \Omega\). A shunt resistance of \(10 \Omega\) is connected in parallel with the ammeter. The reading of the ammeter is _____ mA.

For a given series \(LCR\) circuit it is found that maximum current is drawn when value of variable capacitance is \(2.5 \mathrm{nF}\). If resistance of \(200 \Omega\) and \(100 \mathrm{mH}\) inductor is being used in the given circuit. The frequency of ac source is _______ \(\times 10^3 \mathrm{~Hz}\). (given \(\pi^2=10\) )