The answer to this question is a) sulfur
Answer:
Electric field E = kQ/r^2
Distance between charges = 6.30 - (-4.40) = 10.70m
Say the neutral point, P, is a distance d from q1. This means it is a distance (10.70 - d) from q2.
Field from q1 at P = k(-9.50x^10^-6) / d^2
Field from q2 at P = k(-8.40x^10^-6) / (10.70-d)^2
These fields are in opposite directions and are equal magnitudes if the resultant field = 0
k(-9.50x^10^-6) / d^2 = k(-8.40x^10^-6) / (10.70-d)^2
9.50 / d^2 =8.40 / (10.70-d)^2
d^2 / (10.70-d)^2 = 9.50/8.40 = 1.131
d/(10.70-d) = sqrt(1.1331) = 1.063
d = 1.063 ((10.70-d)
= 10.63 - 1.063d
2.063d = 10.63
d = 5.15m
The y coordinate where field is zero is 6.30 - 5.15 = 1.15m
Explanation:
From the theory we know that:
c = λ / T
f = 1 / T
Where:
c = 3.
/ m (the speed of light)
λ is the wavelengh (in meters)
T is the period (in seconds)
f is the frequency (in Hz)
We were told that:
f = 7.30 .
And we want to find out the value of λ.
c = λ / T
c = λ . 1/T
Swaping 1/T = f
c = λ . f
λ = c / f
λ = 3 .
/ 7.30 . 
λ = 4.12
m
Response: 4.12
m = 412 nm
:-)
1)

<Solve using the formula which is:
Mass=Density×Volume

2)
3)

(Length × Width × Height)


(Answer=7.5)