Answer: 1.8 g
Explanation:
We start first, by calculating the amount of Helium
n = m/M
m = mass of Helium
M = molar mass if Helium
n = 2/4 = 0.5 moles
proceeding further, we use ideal gas law. PV = nRT
Then we have
P1V1/n1T1 = P2V2/n2T2
So that,
n2 = n1T1P2V2/P1V1T2
From the question, we know that, P1 = P2, and T1 = T2. So that,
n2 = n1v2/v1
n2 = (0.5 * 3.9) / 2
n2 = 1.95/2
n2 = 0.975 moles. With this, we can determine the mass, m2 of Helium
n = m/M
m = n * M
m = 0.975 * 3.9
m = 3.8
The difference between both masses are 3.8 - 2 = 1.8 g
Thus, 1.8 g of Helium was added to the cylinder
Answer:
90 degree
Explanation:
Electric field line is vertical to the electric field line.
Answer:
the frequency heard by the observer is equal to 2677 Hz
Explanation:
given,
velocity of the observer = 17 m/s
speed of the sound = 343 m/s
velocity of the source = 0 m/s
frequency emitted from the source = 2550 Hz

velocity of observer is negative as it is approaching the source. f = 2676.38 Hz ≈ 2677 Hz
hence, the frequency heard by the observer is equal to 2677 Hz
Answer:
The correct statement is "The electric field is directed toward the electron and has a magnitude of
".
Explanation:
According to Coulomb's law, the magnitude of the electric field due to a static point charge q at a point r distance away from it is given by

- k is the Coulmob's constant.
The direction of the electric field along the line joining the charge and the point where electric field is to be found and it is directed from positive charge to negative charge.
Conventionally, we assume a positive test charge placed at the point where electric field is to be found, the test charge has very small charge such that its charge does not affect the electric field due to the given charge.
The charge on the electron = -e.
The electric field due to an electron is given by

The direction of this electric field is from positive test charge, placed at the point where electric field is to be found, towards the electron along the line joining the two.
Thus, the correct statement is "The electric field is directed toward the electron and has a magnitude of
".
The answer is a because it never needs to be insulated