The dome of a van de graaff generator has a diameter of 30 cm and is at a potential of +20 000v. calculate : a) the charge on the dome b) the electric field strength at the surface of the dome c) the force on a proton near the surface of the dome

a) radius of the dome r=15 cm

Potential, V=20,000 V

here Q is charge, is permitivity of vacuum and r is the distance from the charge.

b) Electric field (E) strength at the surface of the dome is given by:

c)force on the proton near the surface of the dome:

where E is the electric field and q is the charge of proton.

charge of a proton

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.