The first evidence for electromagnetic waves came from
A) Marconi's experiment in which sound waves were sent from a vibrating membrane in one city and received by a similar device in another city.
B) Heinrich Hertz's experiments in which electrons jumped back and forth across a gap in an electric circuit and EM waves were detected at some distance from the gap.
C) Marconi's experiment in which radio waves were sent from a piece of vibrating crystal in one city and received by a similar device in another city.
D) Heinrich Hertz's experiments in which electric charge was placed on small wooden rod and set into rapid vibration; EM waves were detected by a second wooden rod at some distance from the first rod.
E) Maxwell's experiments in which magnetic effects were demonstrated to result from the current in electrical circuits.
B
You might also like to view...
Impedance: Which one of the following capacitances in series with a 100-? resistor and 15-mH coil will give a total impedance of 110 ? at 2.0 kHz?
A. 0.14 mF B. 46 ?F C. 10 ?F D. 0.56 ?F
Express (2.2 × 106)-1/2 in scientific notation
A) 6.7 × 10-4 B) 1.5 × 103 C) 1.5 × 10-5 D) 1.5 × 104
If the electric field and magnetic field of an electromagnetic wave are given by E = E0 sin(kx - ?t) and B = B0 sin(kx - ?t), and if the value of E0 is 51 µV/m, what is the value of B0? (c = 3.0 × 108 m/s)
A) 1.7 × 1014 T B) 1.7 × 103 T C) 1.7 × 10-14 T D) 1.7 × 104 T E) 1.7 × 10-13 T
The full Moon's apparent magnitude is
A) -1.4. B) -26.2. C) -12.5. D) +4.83. E) +12.7.