A wave travels with a speed of 20 m/s and has a wavelength of 0.800 m. what is the period of the wave? a. 250 ms
b. 40 ms
c. 25 ms
d. 4 ms

b. 40 ms

Explanation:

A wave travels at a speed of 20 m/s

the wavelength is 0.800 m

Required

the period

The expression for the velocity of a wave is given as

substituting our data

But T=1/f

T=1/25

T=0.04s

T=40ms

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.

energy stored in the capacitor= 9.72 x 10⁻⁴ j

explanation:

the energy stored in the capacitor is given by

e= 1/2 c v²

e= energy stored

c= capacitance= 1.5 µc= 1.5 x 10⁻⁶f

v= potential difference=36 v

so energy stored= e= 1/2 (1.5 x 10⁻⁶) (36)²

energy stored= 9.72 x 10⁻⁴j