Electromagnetic Waves

A parallel-plate capacitor of $50\ \mu\text{F}$ contains a dielectric slab of constant ($k$) with the same dimensions. If a time-varying potential difference is applied at a rate of $50\ \text{V/s}$. What is the…

The magnetic field in a travelling electromagnetic wave has a peak value of $20 \mathrm{nT}$. The peak value of electric field strength is

In an electromagnetic wave, the electric and magnetising fields are $100 \mathrm{~V} / \mathrm{m}$ and $0.265 \mathrm{~A} / \mathrm{m}$. The maximum energy flow is

A laser device produces amplification in the

X-ray of wavelength $\lambda=2 \AA$ is emitted from the metal target. The potential difference applied across the cathode and the metal target is

Thermal radiation exist in which part of electromagnetic spectrum?

X-rays and $\gamma$-rays of the same energies may be distinguished by

In which one of the following regions of the electromagnetic spectrum will the vibrational motion of molecules give rise to absorption?

For a colour of light the wavelength for air is $6000 \AA$ and in water the wavelength is $4500 \AA$. Then the speed of light in water will be

The atomic number (Z) of an element whose $k_a$ wavelength is $\lambda$ is 11. The atomic number of an element whose $k_a$, wavelength is $4 \lambda$ is equal to

Electromagnetic waves travel only through

When two different materials A and B having atomic number $Z_{1}$ and $Z_{2}$ are used as the target in Coolidge $\gamma\,$-ray tube at different operating voltage $V_{1}$ and $V_{2}$ respectively their spectrums are…