Question 11 MarkThe formula for displacement $\left( I _d\right)$ is :Answer(c)$\epsilon_0 \frac{d \phi_{ E }}{d t}$View full question & answer→
Question 21 MarkIn any electromagnetic wave, electric and magnetic field are represented by $\vec{E}$ and $\vec{B}$ respectively. The direction of propagation of this wave is along :Answer(c)$\vec{E} \times \vec{B}$View full question & answer→
Question 31 MarkMain source of electromagnetic waves is:Answer(c)Accelerated chargeView full question & answer→
Question 41 MarkRange of wavelength of X-rays is:Answer(b)$10^{-8} m$ to $10^{-13} m$View full question & answer→
Question 51 MarkDisplacement current is same as:Answer(b)Conduction currentView full question & answer→
Question 61 MarkWhich of the following wave is used in long distance communication?Answer(b)Micro wavesView full question & answer→
Question 71 MarkCharacteristic of electromagnetic wave is shown by:Answer(b)Light and X-raysView full question & answer→
Question 81 MarkValue of refractive index for any medium is:Answer(d)$\sqrt{\mu_r \epsilon_r}$View full question & answer→
Question 91 MarkLight waves are:Answer(d)Transverse electromagnetic wavesView full question & answer→
Question 101 MarkIf $\mu_0$ and $\epsilon_0$ be permeability and electrical permittivity of vacuum respectively, then velocity of electromagnetic waves in vacuum is :Answer(b)$\frac{1}{\sqrt{\mu_0 \epsilon_0}}$View full question & answer→
Question 111 MarkPrinciple of existence of electromagnetic waves was given by:Answer(b)MaxwellView full question & answer→
Question 121 MarkWhich of the following waves are not electromagnetic?Answer(b)Sound wavesView full question & answer→
Question 131 MarkOut of the following, waves of which frequency can penetrate ionosphere?Answer(c)Greater than 20 MHzView full question & answer→
Question 141 MarkOzone layer protects us from which harmful radiations coming from the sun?Answer(c)Ultra-violet raysView full question & answer→
Question 151 MarkSpeed of electromagnetic waves in vacuum is:Answer(a)$3 \times 10^8 m / s$View full question & answer→
Question 161 MarkThat part of electromagnetic spectrum which is used to study crystal structure is:Answer(c)X-raysView full question & answer→
Question 171 MarkOut of the following, which colour's wavelength is more than the wavelength of yellow colour?Answer(c)RedView full question & answer→
Question 201 MarkOut of the following, the one whose frequency is minimum is:Answer(a)Infrared raysView full question & answer→
Question 211 MarkOut of the following waves of the Sun, the wave which is used as an electrical energy is:Answer(b)Infrared raysView full question & answer→
Question 231 MarkWhich of the following is an electromagnetic wave?Answer(d)Gamma raysView full question & answer→
Question 241 MarkIn electromagnetic spectrum, the component whose wavelength is minimum is:Answer(a)Gamma raysView full question & answer→
Question 251 MarkElectromagnetic wavesAnswer(a)Follow the principle of superpositionView full question & answer→
Question 261 MarkIf $\lambda_v, \lambda_{ x }$ and $\lambda_{ m }$ represents wavelengths of visible lights, X-rays and microwaves respectively, then :Answer(b)$\lambda_{ m }>\lambda_{ v }>\lambda_{ x }$View full question & answer→