S1: | Electromagnetic waves having wavelengths \(1000\) times smaller than light waves are called X-rays. |
S2: | Ultraviolet waves are used in the treatment of swollen joints. |
S3: | Alpha and gamma rays are not electromagnetic waves. |
S4: | de-Broglie waves are not electromagnetic in nature. |
S5: | Electromagnetic waves exhibit polarization while sound waves do not. |
1. | S1, S4, and S5 |
2. | S3, S4, and S5 |
3. | S1, S3, and S5 |
4. | S2, S3 and S4 |
An EM wave of intensity \(I\) falls on a surface kept in a vacuum and exerts radiation pressure \(P\) on it. Which of the following are true?
(a) | Radiation pressure is \(\frac{I}{c}\) if the wave is totally absorbed. |
(b) | Radiation pressure is \(\frac{I}{c}\) if the wave is totally reflected. |
(c) | Radiation pressure is \(\frac{2I}{c}\) if the wave is totally reflected. |
(d) | Radiation pressure is in the range \(\frac{I}{c}<P<\frac{2I}{c}\) for real surfaces. |
1. (a, b, c)
2. (b, c, d)
3. (a, c, d)
4. (c, d)
Assertion (A): | The fastest speed of propagation of any wave in any medium is the speed of electromagnetic waves in that medium. |
Reason (R): | All signals can at most travel at the speed of light in a vacuum. |
1. | (A) is true but (R) is false. |
2. | (A) is false but (R) is true. |
3. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
4. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
Statement I: | \(c=\frac{1}{\sqrt{\varepsilon_0\mu_0}}.\) | Electromagnetic waves propagate through all media with a speed
Statement II: | Electromagnetic waves can undergo reflection and refraction. |
1. | Statement I is incorrect and Statement II is correct. |
2. | Both Statement I and Statement II are correct. |
3. | Both Statement I and Statement II are incorrect. |
4. | Statement I is correct and Statement II is incorrect. |
The electric field of an electromagnetic wave in free space is given by –
, where t and x are in seconds and metres respectively. It can be inferred that:
(a) The wavelength λ is 188.4 m
(b) The wave number k is 0.33 rad / m
(c) The wave amplitude is 10 V / m
(d) The wave is propagating along + x direction
Which one of the following pairs of statements is correct?
1. (a) and (b)
2. (b) and (c)
3. (c) and (d)
4. (a) and (c)
Assertion (A): | The energy of an electromagnetic wave is not equally distributed among the electric field and magnetic field. |
Reason (R): | \(E_0 ={B_0\over c}\), where c is the velocity of light. | The amplitude of electric field E0 and magnetic field B0 are related by the relation
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |