ch21-sol - Chapter 21 Solution 21.43 From v = f , the...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 21 Solution 21.43 From vf λ = , the wavelength is 8 6 3.00 10 m s 4.00 10 m4 0 0 0 km 75 Hz v f × == = × = The required length of the antenna is then, 41 0 0 0 L , or about 621 miles. Not very practical at all. 21.45 (a) The frequency of an electromagnetic wave is f c = , where c is the speed of light, and is the wavelength of the wave. The frequencies of the two light sources are then Red: 8 14 -9 4.55 10 Hz 660 10 m re f d red c × = × × and Infrared: 8 3.19 10 Hz 940 10 m IR f c × = × × (b) Ignore 21.47 The distance between adjacent antinodes in a standing wave is 2 Thus, ( ) 26.00 cm 12.0 cm 0.120 m = () , and ( ) 98 0.120 m2 . 45 10 Hz cf × 2.94 10 m s = × 21.48 At Earth’s location, the wave fronts of the solar radiation are spheres whose radius is the Sun-Earth distance. Thus, from a va v 2 4 Intensity A r π ÃÃ , the total power is 2 21 1 av 2 W 4 1340 4 1.49 10 m3 . 74 10 W m Inten sit yr ππ ⎛⎞ ⎡⎤ × = × ⎜⎟ ⎢⎥ ⎣⎦ ⎝⎠ P 2 6 21.50 8 6 11.0 m
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/13/2010 for the course PHYSICS 102 taught by Professor Abdulrazzaq during the Fall '08 term at West Virginia State University.

Page1 / 2

ch21-sol - Chapter 21 Solution 21.43 From v = f , the...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online