Answer:
B. -2
Explanation:
The total charge on an atom is the sum of all individual charges present in it. Therefore, the total charge on this atom is given by the following formula:

where,
q = total charge on atom = ?
= no. of protons in the atom = 15
= no. of electrons in the atom = 17
= no. of neutrons in the atom = 12
= charge on proton = +1
= charge on electron = -1
= charge on neutron = 0
Therefore,

Hence the correct option is:
<u>B. -2</u>
A change that would most improve his results would be; D) Connecting the galvanometer to the coil
Answer: 2.67 m/s^2
Explanation:
Centripetal acceleration is defined as v^2/r; in this case, it's 2^2/1.5, which is 2.67.
Answer:
The length of the rope must be an integral multiple of the wavelength of the wave.
Explanation:
The type of waves used by bats are sound waves. Most of the species use their larynx to produce ultrasound waves in the frequency range of 20 to 200 kilohertz.
These sound waves are echoed, reflected, by surroundings, in this case food or prey. These reflections are received by the specialized receptor cells in the ears of bats. The reflections are analyzed by the brain to make an image.
Fun fact: The brain cells of bats are also specialized to better analyze the frequency of ultrasound used by the bat.