Particles with a charge of +5e are incident on a target. If the beam of particles carries a current of 138 µA, how many particles strike the target in a period of 25.0 s? particles

Explanation:

Current (I) is the flow of charge (Q) per unit of time (t). The ampere unit is defined as the amount of charge that flows in one second.

You have the current, 138 µA, and the time, 25.0s, thus you can calculate the charge:

Now calculate the number of particles with a charge of +5eV that have a charge of 0.00345C

The charge of one electron is

Then, a positve charge equivalent to the magnitude of the charge of 5 electrons (one particle) is:

Divide the total charge by the charge of a particle:

Rounding to 3 significant figures that is    

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm