NEET
- Exam
- NEET
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- Physics
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- Electromagnetic Waves
NEET · Physics · Electromagnetic Waves
Electric field associated with EM wave in free space is given by (...
Electric field associated with EM wave in free space is given by (30 \sin \left(6 10^8 \mathrm{t}+\mathrm{kz}\right) \hat{\mathrm{i}} then match the following columns.
(
)
| Column-I | Column-II | ||
| (a) | Direction of propagation of EM wave | (p) | -y axis |
| (b) | Wave length of EM wave | (q) | 2 m^{-1} |
| (c) | Direction of magnetic field of EM wave | (r) | 3.14 m |
| (d) | Propagation constant 'k' of EM wave | (s) | '-z' axis |
Options
- Aa-p, b-r, c-s, d-r
- Ba-s, b-r, c-p, d-q
- Ca-p, b-q, c-s, d-s
- Da-s, b-r, c-p, d-p
Correct answer
B. a-s, b-r, c-p, d-q
Step-by-step solution
The given electric field of the EM wave is:
(E=30 \sin \left(6 10^8 t+k z\right) \hat{i})
Let's break it down:
a) Direction of propagation: The term in the equation indicates that the wave is propagating in the negative -axis (since the sign of is positive in the sine function). Hence, the direction of propagation is along the -z axis.
- b) Wavelength of the EM wave: The propagation constant is related to the wavelength by the formula (k=). From column-II, (k=2, ), so the wavelength (\lambda=3.14, ).
- c) Direction of the magnetic field: Since the electric field is along the -axis and the wave is propagating along the -axis, the magnetic field must be perpendicular to both and hence lies along the -y axis.
- c) Direction of the magnetic field: Since the electric field is along the -axis and the wave is propagating along the -axis, the magnetic field must be perpendicular to both and hence lies along the axis.
d) Propagation constant: As discussed, the propagation constant (k=2, ).
Matching the columns:
- a) Direction of propagation ) -z axis
- b) Wavelength r) 3.14 m
- c) Direction of the magnetic field p) -y axis
- d) Propagation constant q) (2 1)
Thus, the correct answer is:
(2) a-s, b-r, c-p, d-q