A heavy iron bar, of weight \(\mathrm{W}\) is having its one end on the ground and the other on the shoulder of a person. The bar makes an angle \(\theta\) with the horizontal. The weight experienced by the person is _______.

A body of mass \(10\,kg\) is moving with an initial speed of \(20\,m / s\). The body stops after \(5\,s\) due to friction between body and the floor. The value of the coefficient of friction is (Take acceleration due to gravity \(g =10\; ms ^{-2}\))

If \(2.5 \times 10^{-6\,} N\) average force is exerted by a light wave on a non-reflecting surface of \(30\, cm ^{2}\) area during \(40\) minutes of time span, the energy flux of light just before it falls on the surface is .................. \(W / cm ^{2}\) (Round off to the Nearest Integer) (Assume complete absorption and normal incidence conditions are there)

A student measures the time period of \(100\) oscillations of a simple pendulum four times. The data set is  \(90\;s\) ,\(91\;s \), \(95\;s\) and \(92\;s\). If the minimum division in the  measuring clock is \(1\;s\), then the reported mean time should be

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 \({\mkern 1mu} {\mkern 1mu} \frac{1}{{4\pi {\varepsilon _0}}} = 9 \times {10^9}{\mkern 1mu} {\mkern 1mu} N{m^2}{C^{ - 2}}{\rm{ }}\) ]

The frequency of a car horn encountered a change from \(400\, {Hz}\) to \(500\, {Hz}\), when the car approaches a vertical wall. If the speed of sound is \(330\, {m} / {s}\). Then the speed of car is \(.....\,{km} / {h} .\)

A charged particle going around in a circle can be considered to be a current loop. A particle of mass \(m\) carrying charge \(q\) is moving in a plane with speed \(v\) under the influence of magnetic field \(\overrightarrow{ B }\). The magnetic moment of this moving particle

The displacement of a particle executing SHM is given by \(x=10 \sin \left(\omega t+\frac{\pi}{3}\right) \mathrm{m}\). The time period of motion is \(3.14 \mathrm{~s}\). The velocity of the particle at \(\mathrm{t}=0\) is_________ \(\mathrm{m} / \mathrm{s}\).

A rigid square loop of side \(a\) and carrying current \(I_2\) is laying on a horizontal surface near a long current \(I_1\) wire in the same plane as shown in figure. The net force on the loop due to the wire will be

A solenoid having area \(A\) and length ' \(l\) ' is filled with a material having relative permeability 2. The magnetic energy stored in the solenoid is :