Question

last few questions I can not figure out.

Light is identified by the:
1 electromagnetic conduction.
2 electromagnetic induction.
3 pseudo-magnetic construction.
4 neo-magnetic septum.
5 electromagnetic spectrum

Which produces a period of 0.1 seconds?
1 a wave with a frequency of 5 Hz
2 a wave with a wavelength of 7 m
3 a wave with a frequency of 10 Hz
4 a wave with a speed of 5 m/s

The period of a vibrating object is halved if its frequency:

1 triples.
2 increases by one and a half times.
3 increases by three and a half times.
4 quadruples.
5 doubles.