Question

1. An electron which moves with a speed of 4.8 x 10⁴ m/s parallel to a uniform magnetic field of magnitude 0.50 T.

What magnitude does this force experience?

Magnitude = ________

2. Consider 3 polarizers. Polarizer 1 has a vertical transmission axis and polarizer 3 has a horizontal transmission axis. Taken together, polarizers 1 and 3 are a pair of crossed polarizers. Polarizer 2, with a transmission axis of 30 degrees to the vertical, is placed between polarizers 1 and 3.

What is the intensity of light transmission through these polarizers given an initial intensity of light I₀?

a. 0.25 I₀

b. 0.375 I₀

c. zero

d. 0.18 I₀

e. 0.09 I₀

3.

Which of the following pictures represents the orientation of the electric field, magnetic field and velocity of an electromagnetic wave? 200 vy <6 ? . کا y A Select the best option from the choices below: бро А ос о в Grad Dedud

Answer 1

solution (1) Given speed of electron V = 4.8 x 10 m/s and magnitude of magnetic field = 0.50T As we know magnetic force = q (V x B) As given speed of the electron is parallel to direction of magnetic field so die VX B =0 If magnetic) = q (7x) co Magnitude = Kero. (2) Given a P-3 P-2 P-1 initial intensity of light to crossing the polarisen 1 the Given After intensity is 10% Then after coussing poloriser 2 the intensity becomes = To cos? (30°) ( " By Malus law.) Finally after crossing polariser 3 the intensity becomes = To cos? 30 cost (90-30) & = 10 sino 10 x 0.75 = 0.0920

. In a electromagnetic wave, electreêc field is always perpendicailar to the magnetic field, and both fields are directed at reight angles. to the direction of propagation of the wave. So y along the dêrcection Ext. So from the given pictures option (B) is right. 212