This seems like an incomplete question..
Answer: 20.4752789138x x 10^23 atoms
To count how many atoms in moles you need to know Avogadro's number. Avogadro's number dictate that for every mole there is 6.022140857 × 10^23 molecule/atoms.
Then 3.4 moles of helium will be 3.4x 6.022140857 x 10^23 atoms= 20.4752789138x x 10^23 atoms
Answer:
e. 1.2 x 10²³
Explanation:
According to the problem, The current equation is given by:

Here time is in seconds.
Consider at t=0 s the current starts to flow due to battery and the current stops when the time t tends to infinite.
The relation between current and number of charge carriers is:

Here the limits of integration is from 0 to infinite. So,


q = 1.90 x 10⁴ C
Consider N be the total number of charge carriers. So,
q = N e
Here e is electronic charge and its value is 1.69 x 10⁻¹⁹ C.
N = q/e
Substitute the suitable values in the above equation.

N = 1.2 x 10²³
Answer:
See explanation
Explanation:
We have to convert to angular velocity in rads-1 as follows;
Angular velocity in rad/s = 2π/60 × 1900 rpm = 199 rad/s
Given that
angular velocity =angle turned /time taken
Time taken = angle turned/angular velocity
Converting 35° to radians we have;
35 × π/180 = 0.61 radians
Time taken = 0.61 radians/199 rad/s
Time taken = 0.0031 seconds
A. 22 Million...........................................................