Question

The electron gun in a television tube uses a uniform electric field to accelerate electrons from rest to 4.0×107 m/s in a distance of 1.3 cm. What is the electric field strength?

Answer 1

350,000 V/m

Step-by-step explanation:

v₁ = 0

v₂ = 4.0 × 10⁷ m/s

q = 1.6 × 10⁻¹⁹ C

m = 9.1 × 10⁻³¹ kg

d = 1.3 cm = 1.3 × 10⁻² m

v₂² - v₁² = -2q/m × ΔV

`(4.0*10^7)^2-0=-(2(1.6*10^(-19)))/(9.1*10^(-31)) *\Delta V`

ΔV = 4550 V

E = ΔV/d

= 4550/(1.3 × 10⁻²)

= 350,000 V/m