When the wavelength of radiation falling on a metal is changed from \(500 \,nm\) to \(200\, nm ,\) the maximum kinetic energy of the photoelectrons becomes three times larger. The work function of the metal is close to\(.....eV\)

In an experiment a convex lens of focal length \(15\, cm\) is placed coaxially on an optical bench in front of a convex mirror at a distance of \(5\,cm\) from it. It is found that an object and its image coincide, if the object is placed at a distance of \(20\,cm\) from the lens. The focal length of the convex mirror is.......\(cm\)

In an experiment for estimating the value of focal length of converging mirror, image of an object placed at \(40\,cm\) from the pole of the mirror is formed at distance \(120\,cm\) from the pole of the mirror. These distances are measured with a modified scale in which there are \(20\) small divisions in \(1\,cm\). The value of error in measurement of focal length of the mirror is \(1 / K\) \(cm\). The value of \(K\) is  \(..........\)

A cylinder of fixed capacity of \(44.8 \,litres\) contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of gas in the cylinder by \(20.0^{\circ} C\) will be ..............  \(J\)(Given gas constant \(R =8.3 \,JK ^{-1}- moI ^{-1}\) )

A block of mass \(10\, kg\) starts sliding on a surface with an initial velocity of \(9.8\, ms ^{-1}\). The coefficient of friction between the surface and bock is \(0.5\). The distance covered by the block before coming to rest is: [use \(g =9.8\, ms ^{-2}\) ].........\(m\)

A particle of mass \(m\) projected with a velocity ' \(u\) ' making an angle of \(30^{\circ}\) with the horizontal. The magnitude of angular momentum of the projectile about the point of projection when the particle is at its maximum height \(\mathrm{h}\) is _______.

The dimensions of angular momentum , latent heat and capacitance are, respectively.

For a series \(LCR\) circuit with \({R}=100\,\ \Omega, {L}=0.5\, {mH}\) and \({C}=0.1\, {pF}\) connected across \(220 \,{V}-50\, {Hz}\) \(AC\) supply, the phase angle between current and supplied voltage and the nature of the circuit is :

At some location on earth the horizontal component of earth’s magnetic field is \(18\times10^{-6}\,T\). At this location, magnetic needle of length \(0.12\, m\) and pole strength \(1.8\, A\,m\) is suspended from its mid-point using a thread, it makes \(45^o\) angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force that should be applied at one of its ends is

A charge \('q'\) is placed at one corner of a cube as shown in figure. The flux of electrostatic field \(\overrightarrow{ E }\) through the shaded area is ...... .

The reverse breakdown voltage of a Zener diode is \(5.6\, V\) in the given circuit. The current \(I_z\) through the Zener is......\(mA\)