When a beam of white light is allowed to pass through convex lens parallel to principal axis, the different colours of light converge at different point on the principle axis after refraction. This is called:

The equivalent resistance between points \(A\) and \(B\) in the given network is ............ \(\Omega\)

A moving coil galvanometer has resistance \(50\,\Omega \) and it indicates full deflection at \(4\,mA\) current. A voltmeter is made using this galvanometer and a \(5\,k\Omega \) resistance. The maximum voltage, that can be measured using this voltamenter, will be close to ......\(V\)

In a meter bridge, the wire of length \(1\, m\) has a nonuniform cross-section such that, the variation \(\frac{{dR}}{{d\ell }}\) of its resistance \(R\) with length \(\ell \) is \(\frac{{dR}}{{d\ell }} \propto \frac{1}{{\sqrt \ell  }}\) Two equal resistances are connected as shown in the figure. The galvanometer has zero deflection when the jockey is at point \(P\). What is the length \(AP\) ? ................ \(m\)

In a coil, the current changes form \(-2 \mathrm{~A}\) to \(+2 \mathrm{~A}\) in \(0.2 \mathrm{~s}\) and induces an emf of \(0.1 \mathrm{~V}\). The selfinductance of the coil is _______.

A coil is placed in a time varying magnetic field. If the number of turns in the coil were to be halved and the radius of wire doubled, the electrical power dissipated due to the current induced in the coil would be: (Assume the coil to be short circuited.)

The velocity of water in a river is \(18\, km/h\) near the surface. If the river is \(5\, m\) deep, find the shearing stress between the horizontal layers of water. The co-efficient of viscosity of water \(= 10^{-2}\,,poise\)

A body takes \(4\, {min}\). to cool from \(61^{\circ} {C}\) to \(59^{\circ} {C}\). If the temperature of the surroundings is \(30^{\circ} {C}\), the time taken by the body to cool from \(51^{\circ} {C}\) to \(49^{\circ} {C}\) is \(....\,min\)

The speed of electrons in a scanning electron microscope is \(1 \times 10^{7} \,ms ^{-1}\). If the protons having the same speed are used instead of electrons, then the resolving power of scanning proton microscope will be changed by a factor of:

A Zener diode is connected to a battery and a load as show below: The currents, \(I, I_Z\) and \(I_L\) are respectively .