The magnetic field in a plane electromagnetic wave is given by:
\(B_y = 2\times10^{-7} ~\text{sin}\left(\pi \times10^{3}x+3\pi\times10^{11}t\right )\text{T}\)
The wavelength is:
1. \(\pi\times 10^{3}~\text{m}\)
2. \(2\times10^{-3}~\text{m}\)
3. \(2\times10^{3}~\text{m}\)
4. \(\pi\times 10^{-3}~\text{m}\)
1. | Ultraviolet rays | 2. | \(X\)-rays |
3. | Gamma-rays | 4. | Microwaves |
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. \( I_d=\frac{V_0}{\omega C} \cos \omega t\)
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. \(10\times 10^{3}~\text{J}\)
1. | \(1:1\) | 2. | \(1:c\) |
3. | \(1:c^2\) | 4. | \(c:1\) |
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) |
1. | \(\lambda_\gamma<\lambda_X<\lambda_I<\lambda_M\) |
2. | \(\lambda_M<\lambda_I<\lambda_X<\lambda_\gamma\) |
3. | \(\lambda_X<\lambda_\gamma<\lambda_M<\lambda_I\) |
4. | \(\lambda_X<\lambda_I<\lambda_\gamma<\lambda_M\) |
1. | \(10\hat i~\text{nT}\) | 2. | \(-10\hat i~\text{nT}\) |
3. | \(\hat i~\text{nT}\) | 4. | \(-\hat i~\text{nT}\) |