Answer: a) 73.41 10^-12 F; b)4.83* 10^3 N/C; c) 3.66 *10^3 N/C
Explanation: To solve this problem we have to consider the following: The Capacity= Charge/Potential Difference
As we know the capacity is value that depend on the geometry of the capacitor, in our case two concentric spheres.
So Potential Difference between the spheres is given by:
ΔV=-
Where E = k*Q/ r^2
so we have 
then
Vb-Va=k*Q(1/b-1/a)=kQ (ab/b-a)
Finally using C=Q/ΔV=ab/(k(b-a))
To caclulate the electric firld we first obtain the charge
Q=ΔV*C=120 V*73.41 10^-12 F=8.8 10^-9 C
so E=KQ/r^2 for both values of r
r=12.8 cm ( in meters)
r2=14.7 cm
E(r1)=4.83* 10^3 N/C
E(r2)=3.66 *10^3 N/C
I’m not Vietnamese but I think your asking for this, for people who understand Vietnamese pls help them :d
C. change length and direction
Explanation:
The density of the material in which the light wave is travelling affects the speed of the wave. Different materials have different densities and they effect differently light waves which travel through them. Light waves may change direction at the boundary between two transparent materials, depending on material density. Density also impacts the speed of light. The denser the material, the slower light travels through it. The wavelength also decreases as light travels through the denser medium.
Answer:
After a male ejaculates, many sperms move to the upper vagina (via contractions from the vagina) through the cervix and across the length of the uterus, reaching the fallopian tubes. Here they will meet the egg cell ready to be fertilized
Answer:
Force, F = 77 N
Explanation:
A child in a wagon seem to fall backward when you give the wagon a sharp pull forward. It is due to Newton's third law of motion. The forward pull on wagon is called action force and the backward force is called reaction force. These two forces are equal in magnitude but they acts in opposite direction.
We need to calculate the force is needed to accelerate a sled. It can be calculated using the formula as :
F = m × a
Where
m = mass = 55 kg
a = acceleration = 1.4 m/s²
F = 77 N
So, the force needed to accelerate a sled is 77 N. Hence, this is the required solution.
