11. (11) Electrons travel at a speed of 6.0 × 107 m/s in a television tube. The

Question

11. (11) Electrons travel at a speed of 6.0 × 107 m/s in a television tube. The electrons are affected by Earth's magnetic field. The tube, which is 0.40 m long, is located at a region where the mag netic field has a vertical component of 18 T and a horizontal component of 24 HT (Fig. 28-30). If the initial direction of the electron beam is in the same direction as the horizontal compo- nent of Earth's magnetic field, in which direction, and by how much, is the electron beam deflected? .X FIGURE 28-30 Problem 11.

Explanation / Answer

consider the motion along the X-direction :

v = velocity = 6 x 107 m/s

x = distance travelled = length of tube = 0.40 m

t = time taken to travel through the tube

Using the equation

t = x/v

t = 0.40/(6 x 107) = 6.67 x 10-9 sec

consider the motion along the Y-direction :

magnetic force is given as

F = q vx Bz = (1.6 x 10-19) (6 x 107) (18 x 10-6) = 1.73 x 10-16 N

acceleration is given as

a = F/m = (1.73 x 10-16)/(9.1 x 10-31) = 1.9 x 1014 m/s2

voy = initial velocity along Y-direction = 0 m/s

t = time of travel = 6.67 x 10-9 sec

y = deflection along Y-direction

using the equation

y = voy t + (0.5) a t2

y = 0 (6.67 x 10-9) + (0.5) (1.9 x 1014) (6.67 x 10-9)2

y = 0.0042 m

negative y-direction

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.