The answers are B, C, E and F.
Atoms from an element is mostly made of protons, neutrons, and electrons. Proton numbers are like a class number for each element. Each element has their own and they're all different. And the number of protons are equal to the number of electrons. Therefore, B is correct.
Isotopes. It's different atoms from a same element that has the same number of protons but different number of neutrons. For example in hydrogen, there's 3 Isotopes for hydrogen. Therefore, C is correct.
Again, proton for the same element is never changed, even if they're different Isotopes. So, E is correct.
Isotopes, again, different elements may have different Isotopes. Some has only 1, others may have a few or more. So, F is correct too.
Answer:

Explanation:
When she moved a distance of 1 m from mid point she observe first destructive interference due to two speakers
so we can say that path difference of sound due to two speakers will be equal to half of the wavelength
so path difference is given as

so it will be


now we know that


now frequency of sound is given as



Answer:

Explanation:
Given that;
I₀ = 9.55 A
f = 359 cycles/s
b = 72.2 cm
c = 32.5 cm
a = 80.2 cm
Using the formula;

where;



Replacing our values into above equation; we have:



Then the
is calculated as:



Answer:
ow much work was done? W = F xD. IN X 2m = 2;. 2. A force of 15 newtons is ... 3. It took 50 joules to push a chair 5 meters across the floor. With what force was ... was done. How far was the rock lifted? W=FXD. D=1500 = 1.5m. Answer: :.5m ... A young man exerted a force of 9,000 newtons on a stalled car, but he was.
Explanation:
Answer:

Explanation:
Use the velocity formula to solve

In this question, you are given velocity
, and you are given a distance,
. Time in this question is what you'll need to find.
Start by rearranging the velocity formula, to isolate for t.

Start by multiplying both sides by t

Then divide both sides by v.

Now that you've isolated for time, sub in your values and calculate.
