List -I (Electromagnetic waves) | List - II (Wavelength) |
(a) AM radio waves | (i) \(10^{-10}~\mathrm{m}\) |
(b) Microwaves | (ii) \(10^{2} \mathrm{~m}\) |
(c) Infrared radiation | (iii) \(10^{-2} \mathrm{~m}\) |
(d) X-rays | (iv) \(10^{-4} \mathrm{~m}\) |
(a) | (b) | (c) | (d) | |
1. | (ii) | (iii) | (iv) | (i) |
2. | (iv) | (iii) | (ii) | (i) |
3. | (iii) | (ii) | (i) | (iv) |
4. | (iii) | (iv) | (ii) | (i) |
If \(\lambda_X,\lambda_I,\lambda_M\) and \(\lambda_\gamma\) are the wavelengths of \(X\)-rays, infrared rays, microwaves and \(\gamma\)-rays respectively, then:
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. | \(\lambda_X<\lambda_I<\lambda_\gamma<\lambda_M\) |
An electromagnetic wave is moving along negative \(\text{z (-z)}\) direction and at any instant of time, at a point, its electric field vector is \(3\hat j~\text{V/m}\). The corresponding magnetic field at that point and instant will be: (Take \(c=3\times10^{8}~\text{ms}^{-1}\) )
1. \(10\hat i~\text{nT}\)
2. \(-10\hat i~\text{nT}\)
3. \(\hat i~\text{nT}\)
4. \(-\hat i~\text{nT}\)
1. | \(3 \times 10^{-8} \cos \left(1.6 \times 10^3 x+48 \times 10^{10} t\right) \hat{i}~\text{ V/m}\) |
2. | \(3 \times 10^{-8} \sin \left(1.6 \times 10^3 \mathrm{x}+48 \times 10^{10} \mathrm{t}\right) \hat{\mathrm{i}}~ \mathrm{V} / \mathrm{m}\) |
3. | \(9 \sin \left(1.6 \times 10^3 \mathrm{x}-48 \times 10^{10} \mathrm{t}\right) \hat{\mathrm{k}} ~~\mathrm{V} / \mathrm{m}\) |
4. | \(9 \cos \left(1.6 \times 10^3 \mathrm{x}+48 \times 10^{10} \mathrm{t}\right) \hat{\mathrm{k}}~~\mathrm{V} / \mathrm{m}\) |
For a plane electromagnetic wave propagating in the x-direction, which one of the following combinations gives the correct possible directions for the electric field \((E)\) and magnetic field \((B)\) respectively?
1. \(\hat{j}+\hat{k},~-\hat{j}-\hat{k}\)
2. \(-\hat{j}+\hat{k},~-\hat{j}+\hat{k}\)
3. \(\hat{j}+\hat{k},~\hat{j}+\hat{k}\)
4. \(-\hat{j}+\hat{k},~-\hat{j}-\hat{k}\)