VISUAL PHYSICS ONLINE

8.1 FROM THE UNIVERSE TO THE ATOM

THE ATOM

P81 005

(A) What is the name of the device shown below?

(b) What is the purpose of the device?

(C) What is the name and function of the parts labelled A to F?

In a special investigation, the voltage between the cathode and the anode is

increased so that an electron gains a velocity of 0.60 c, where c is the speed of

light. The electron starts from rest at the cathode.

(D) What was the accelerating voltage for the electron gun?

The deflection plates are separated by 18.0 mm and the voltage across them is 254 V.

(E) What is strength of the electric field between the plates?

(F) What is the electric force acting on an electron?

(G) What acceleration of the electron?

View solution below only after you have completed the answering the question.

Solution

(A) CRO – cathode ray tube

(B) Cathode ray tubes using in televisions and cathode ray tubes

(C) A – low voltage to provide current to heat cathode

B – hot cathode – electron gun

C – accelerating voltage – large used to accelerate electrons to give them large kinetic energies

D – accelerating voltage plates

E – electric deflecting plates – to change the path of the electron beam

F – fluorescent screen – when an electron hits the screen a flash of light is emitted

(D)

(E)

(E)

(G)