The atomic mass of an element is equal to the number of:

A: protons

B: protons plus neutrons

C: protons plus electrons

D: neutrons

Do electromagnetic waves travel through a medium

Zirconium has an atomic number of 40. How many neutrons are there in an isotope of zirconium-92? A. 40 B. 52 C. 92 D. 132

A loudspeaker is placed between two observers who are 125 apart, alonq the line connecting them. If one observer (observer A) records a sound level of 55 dB and the other (observer B) records a sound level of 85 dB, how far is the speaker from each

5. If you rub a balloon on a piece of fabric or carpeting and then hold it against your head, your hair can stand on end. Use what you have learned in this lesson to explain why this happens.

Explain how Copernicus concluded that stars were farther away than planets. Draw a diagram showing how this principle applies to another example.

When one of the electrons of a particular atom undergoes a transition to a quantum state of lower energy, it a) collides with another of its electrons b) exchanges quantum states with another of its electrons c) undergoes a transition to a quantum

What's the symbol for an ionized bromine atom?

What is the hottest layer in the Sun's atmosphere?

Which do you need to calculate the speed of a wave? A. distance and frequency B. distance and time C. time and frequency

What is one of the benefits that scientists have discovered from organisms' daily exposure to radioisotopes? 1. being able to Carbon date fossils 2. X-ray Imaging capability 3. radiation treatment for cancer 4. invention of microwave cooking