I need to check my answers!!

Which of these is not in the family
a. sound
b. light
c. infrared radiation (answer)
d. radio waves

When an electric charge is shaken to and fro in quick succession, the vibrating charge emits
a. infrasonic sound
b. Ultrasonic sound
c. an electromagnetic wave (answer)
d. gamma radiation

If you dip your finger repeatedly onto the surface of still water, you produce waves. The more frequently you dip your finger, the
a. lower the wave frequency and the longer the wavelength
b. higher the wave frequency and the shorter the wavelength (answer)
c. both of the above
d. neither

Low-pitched sounds have
a. low frequencies
b. long periods
c. both (answer)
d. none

The first answer is wrong. Infrared, light, and radio waves are electromagnetic radiation. Sound is not.

The others look ok to me.

To check your answers:

1. "Which of these is not in the family?" The correct answer is option c. infrared radiation.

2. "When an electric charge is shaken to and fro in quick succession, the vibrating charge emits..." The correct answer is option c. an electromagnetic wave.

3. "If you dip your finger repeatedly onto the surface of still water, you produce waves. The more frequently you dip your finger, the..." The correct answer is option b. higher the wave frequency and the shorter the wavelength.

4. "Low-pitched sounds have..." The correct answer is option c. both low frequencies and long periods.

By following the explanation, you can understand how to arrive at the correct answers.