zero
clockwise
counterclockwise
clockwise in the left side and counterclockwise in the right side
counterclockwise in the left side and clockwise in the right side
The current i is from left to right in the conductor as shown in Fig. 4. The magnetic positivefield B is upward and point S is at a higher potential than point T. The charge carriers are
positive
neutral
negative
absent
unable to be identified.
+0.66A, −0.66A
+0.5A , 0A
+1.0A, +0.5A
+0.66A , −0.5A
−0.66A , 0A
As shown in Fig. 7, a moving point source S with speed v = 20m/s heading toward the wall on the right generates sound wave with frequency 50KHz. The speed of sound in air is 340m/s. What’s the beat frequency heard at D
2.95KHz
1.45KHz
0.50KHz
5.90KHz
8.53KHz
The average speed v and molecular diameter d of five ideal gases are given below. The number of molecules per unit volume is the same for all of them. Which gas has the greatest mean free path?
A stopping potential of 4.2V is needed for radiation whose wavelength is 200nm. The work function in eV of the
4
3
5
6
2
Polarization experiments provide evidence that
light is a longitudinal wave.
light is a stream of particles.
light is a transverse wave.
the polarized light is monochromatic.
polarized light propagates faster than un-polarized light.
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