The purpose of a fuse or circuit breaker is
to speed up the current
to slow down the current
to stop current that is flowing too fast
to stop current that is flowing too slow

What a sloppy question ! The purpose of a fuse or circuit breaker is to shut down the circuit when current reaches a magnitude indicating danger due to a serious malfunction. When current IS flowing in the circuit, it's always flowing at the same speed.

6.4 x 10^14Hz

Explanation:

velocity of blue light (V) = 3.0 x 10^8m/sec

wavelength (λ) = 465 nanometers

(4.65 x 10?m)

Since 1nanometer = 1 x 10^-9 meter

465 nanometer = 4.65 x 10^-7 meters

frequency (F) = ?

Recall that the frequency of a wave is the number of cycles the wave complete in one second, and its unit is Hertz.

So, apply the formula V = F λ

3.0 x 10^8m/sec = F x 4.65 x 10^-7 meters

F = (3.0 x 10^8m/sec / 4.65 x 10^-7 meters)

F = 6.4 x 10^14Hz

Thus, the frequency of the blue light is 6.4 x 10^14Hz