Question

An alpha particle (α), which is the same as a helium-4 nucleus, is momentarily at rest in a region of space occupied by an electric field. The particle then begins to move. Find the speed of the alpha particle after it has moved through a potential difference of −3.45×10−3 V .The charge and the mass of an alpha particle are qα = 3.20×10−19 C and mα = 6.68×10−27 kg , respectively.

Mechanical energy is conserved in the presence of which of the following types of forces? (Select all that apply.)

(A) electrostatic
(B) frictional
(C) magnetic
(D) gravitational

Answer 1

`v = 0.57 *  10^3 m/s`

Mechanical energy is conserved in the presence of following forces:

a) electrostatic force

b) magnetic force

c) gravitational force

Step-by-step explanation:

Give data:

potential difference ,
`V = - 3.45 * 10^(-3) V`

we Know change in potential energy is given as

`U = V* Q`

`U = - 3.45 * 10^(-3) * 3.2* 10^(-19)`

`U = - 1.10 * 10^(-21) J`

therefore, change in potential energy U is
`U = - 1.10 * 10^(-21)J`

let speed of particle is v

from energy conservation theorem

loss of electrical PE = KE gained

`1.1* 10^(-21) = 0.5 * 6.68 * 10^(-27) * v^2`

solving for v

`v = 0.57 *  10^3 m/s`

Mechanical energy is conserved for following forces:

a) electrostatic force

b) magnetic force

c) gravitational force