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

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

Electromagnetic waves travel only through

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

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

Thermal radiation exist in which part of electromagnetic spectrum?

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

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

A laser device produces amplification in the

A laser beam of power$27 \mathrm{mW}$ has a cross-sectional area of $10 \mathrm{mm}^{2}$. The magnitude of the maximum electric field in this electromagnetic wave is given by $[$Given permittivity of…