Given that the frequency of an EM wave is 4THz, what is the wavelength?

B. 75,000nm

Explanation:

The wavelength of a wave can be calculated thus;

λ = v/f

Where;

λ = wavelength (m)

v = velocity of light = 3 × 10^8m/s

f = frequency (Hz)

According to this question, the EM wave has a frequency of 4THz i.e. 4 Terahertz = 4 × 10^12Hz

λ = 3 × 10^8 ÷ 4 × 10^12

λ = 3/4 × 10^(8-12)

λ = 0.75 × 10^-4

λ = 0.000075m

Based on the options given, this value is equivalent to 75,000nm, which means 75000 × 10^-9m.

c.the charges if the proton and electron and gravity

12000j is work done