G12_WAVE

A wave travels with a speed of 300 m/s and has a wavelength of 0.75 m. What is its frequency?

• A. 200 Hz

• B. 250 Hz

• C. 300 Hz

• D. 400 Hz

If the frequency of a sound wave is 500 Hz, what is its period?

• A. 0.002 s

• B. 0.005 s

• C. 0.01 s

• D. 2.0 s

A string vibrates at a frequency of 120 Hz producing a wave with wavelength 2.5 m. What is the wave speed?

• A. 300 m/s

• B. 250 m/s

• C. 200 m/s

• D. 150 m/s

If the power of a sound source is 5.0 W and it spreads uniformly in all directions, what is the intensity at a distance of 2.0 m?

• A. 1.0 W/m²

• B. 0.20 W/m²

• C. 0.1 W/m²

• C. 0.40 W/m²

A police siren emits sound at 800 Hz. If the police car approaches a stationary observer at 30 m/s (speed of sound = 340 m/s, what frequency does the observer hear?

• A. 788 Hz

• B. 878 Hz

• C. 878 m/s

• D. 900 Hz

What is the speed of an electromagnetic wave in vacuum?

• 2.5×10^8 m/s
• 5.0×10^7 m/s
• 4.0×10^8 m/s
• A. 3.0×10^8 m/s

The waves have a frequency of 2.5 Hz. Determine the amplitude.

• 7.50mm

• 25cm

• 3.75mm

• 187.5mm

What is the phase difference of the 2 waves?

• 180 degrees

• 360 degrees

• 45 degrees

• 90 degrees

The wave in the diagram below has a speed of 340 m s^–1.

What is the frequency and wavelength of the wave?

• f=321 Hz ; wavelength= 0.095 cm

• f=95.2Hz ; wavelength= 0.12m

• f=3571Hz ; wavelength= 0.095 m

• f=35.70Hz ; wavelength= 95 km

A police car siren emits a sound wave with a frequency of 450 Hz. The car is travelling away from an observer at speed of 45 m s^-1. The speed of sound is 340 m s^-1.

Which of the following is the frequency the observer hears?

           

             

             

• A. 519 Hz   

• B. 483 Hz 

• C. 397 Hz 

• D. 358 Hz