A sinusoidal wave moving to the left has a wavelength of 5.0 cm and a frequency of 50 Hz. At t = 0 s, the wave has a crest at x = 0 cm. What is the earliest time after t = 0 s at which there is a crest at the position x = 3.5 cm?

0.006 seconds

Explanation:

Were are told that:

At t = 0 s, the wave has a crest at x = 0 cm.

The distance between two consecutive wavelength ( λ ) given by the sinusoidal wave = 5.0 cm

And; Velocity can be expressed as: fλ

where f = 50 Hz

Velocity (V) = 50 × 5.0

V = 250 cm/s

If the crest is moved to a distance of 5.0 cm to 3.5 cm; then the distance traveled = (5.0 - 3.5) cm

= 1.5 cm

However; the earliest time (t) by the wave will be : = 0.006 seconds

b) phosphorus pentoxide

so easy. just google the electromagnetic waves and it’ll pop up.