For a transparent medium relative permeability and permittivity, \(\mu_r\) and \(\varepsilon_r\) are \(1.0\) and \(1.44\) respectively. The velocity of light in this medium would be:
1. | \(2.5\times 10^{8}~\text{m/s}\) | 2. | \(3\times 10^{8}~\text{m/s}\) |
3. | \(2.08\times 10^{8}~\text{m/s}\) | 4. | \(4.32\times 10^{8}~\text{m/s}\) |
A parallel plate capacitor of capacitance \(20~\mu\text{F}\) is being charged by a voltage source whose potential is changing at the rate of \(3~\text{V/s}\). The conduction current through the connecting wires, and the displacement current through the plates of the capacitor, would be, respectively:
1. zero, zero
2. zero, \(60~\mu\text{A}\)
3. \(60~\mu\text{A}\), \(60~\mu\text{A}\)
4. \(60~\mu\text{A}\), zero
Which colour of the light has the longest wavelength?
1. violet
2. red
3. blue
4. green
The ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic wave is: (\(c\) = speed of electromagnetic waves)
1. | \(1:1\) | 2. | \(1:c\) |
3. | \(1:c^2\) | 4. | \(c:1\) |
Light with an average flux of \(20~\text{W/cm}^2\) falls on a non-reflecting surface at normal incidence having a surface area \(20~\text{cm}^2\). The energy received by the surface during time span of \(1\) minute is:
1. \(12\times 10^{3}~\text{J}\)
2. \(24\times 10^{3}~\text{J}\)
3. \(48\times 10^{3}~\text{J}\)
4. \(10\times 10^{3}~\text{J}\)
The EM wave with the shortest wavelength among the following is:
1. | Ultraviolet rays | 2. | \(X\)-rays |
3. | Gamma-rays | 4. | Microwaves |
The magnetic field in a plane electromagnetic wave is given by:
\(B_y = 2\times10^{-7} \text{sin}\left(\pi \times10^{3}x+3\pi\times10^{11}t\right )T\)
The wavelength is:
1. \(\pi\times 10^{3}~\text{m}\)
2. \(2\times10^{-3}~\text{m}\)
3. \(2\times10^{3}~\text{m}\)
4. \(\pi\times 10^{-3}~\text{m}\)
A capacitor of capacitance \(C\) is connected across an AC source of voltage \(V\), given by;
\(V=V_0 \sin \omega t\)
The displacement current between the plates of the capacitor would then be given by:
1. \( I_d=\frac{V_0}{\omega C} \sin \omega t \)
2. \( I_d=V_0 \omega C \sin \omega t \)
3. \( I_d=V_0 \omega C \cos \omega t \)
4. \( I_d=\frac{V_0}{\omega C} \cos \omega t\)
List -I (Electromagnetic waves) | List - II (Wavelength) |
(a) AM radio waves | (i) \(10^{-10}~\text{m}\) |
(b) Microwaves | (ii) \(10^{2} ~\text{m}\) |
(c) Infrared radiation | (iii) \(10^{-2} ~\text{m}\) |
(d) \(X\)-rays | (iv) \(10^{-4} ~\text{m}\) |
(a) | (b) | (c) | (d) | |
1. | (ii) | (iii) | (iv) | (i) |
2. | (iv) | (iii) | (ii) | (i) |
3. | (iii) | (ii) | (i) | (iv) |
4. | (iii) | (iv) | (ii) | (i) |