The electric field of an electromagnetic wave in free space is given by $\overrightarrow{\mathrm{E}}=10 \cos \left({10}^7\mathrm{t}+\mathrm{kx}\right)\hat{\mathrm{j}} \mathrm{V}/\mathrm{m}$, where t and x are in seconds and metres respectively. It can be inferred that

1) the wavelength $\mathrm{\lambda }$ is 188.4 m

2) the wave number k is 0.33 rad/m.

3) the wave amplitude is 10 V/m.

4) the wave is propagating along + x direction.

Which one of the following pairs of statements is correct ?

• A

  (3) and (4)

• B

  (1) and (2)

• C

  (2) and (3)

• D

  (1) and (3)