An inductor of inductance $$L$$ and resistor $$R$$ are joined together in series and connected by a source of frequency $$\omega$$. The power dissipated in the circuit is
An electromagnetic wave is travelling in $$x$$-direction with electric field vector given by, $$\mathbf{E}_y=E_0 \sin (k x-\omega t) \hat{\mathbf{j}}$$. The correct expression for magnetic field vector is
The phenomenon involved in the reflection of radio-waves by ionosphere is similar to
A point object is moving uniformly towards the pole of a concave mirror of focal length $$25 \mathrm{~cm}$$ along its axis as shown below. The speed of the object is $$1 \mathrm{~ms}^{-1}$$. At $$t=0$$, the distance of the object from the mirror is $$50 \mathrm{~cm}$$. The average velocity of the image formed by the mirror between time $$t=0$$ and $$t=0.25 \mathrm{~s}$$ is